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6de9cd9a | 1 | /* Optimization of PHI nodes by converting them into straightline code. |
5624e564 | 2 | Copyright (C) 2004-2015 Free Software Foundation, Inc. |
6de9cd9a DN |
3 | |
4 | This file is part of GCC. | |
0385f644 | 5 | |
6de9cd9a DN |
6 | GCC is free software; you can redistribute it and/or modify it |
7 | under the terms of the GNU General Public License as published by the | |
9dcd6f09 | 8 | Free Software Foundation; either version 3, or (at your option) any |
6de9cd9a | 9 | later version. |
0385f644 | 10 | |
6de9cd9a DN |
11 | GCC is distributed in the hope that it will be useful, but WITHOUT |
12 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
13 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
14 | for more details. | |
0385f644 | 15 | |
6de9cd9a | 16 | You should have received a copy of the GNU General Public License |
9dcd6f09 NC |
17 | along with GCC; see the file COPYING3. If not see |
18 | <http://www.gnu.org/licenses/>. */ | |
6de9cd9a DN |
19 | |
20 | #include "config.h" | |
21 | #include "system.h" | |
22 | #include "coretypes.h" | |
4a8fb1a1 | 23 | #include "hash-table.h" |
6de9cd9a | 24 | #include "tm.h" |
40e23961 MC |
25 | #include "hash-set.h" |
26 | #include "machmode.h" | |
27 | #include "vec.h" | |
28 | #include "double-int.h" | |
29 | #include "input.h" | |
30 | #include "alias.h" | |
31 | #include "symtab.h" | |
32 | #include "wide-int.h" | |
33 | #include "inchash.h" | |
6de9cd9a | 34 | #include "tree.h" |
40e23961 | 35 | #include "fold-const.h" |
d8a2d370 | 36 | #include "stor-layout.h" |
3a3f4da9 | 37 | #include "flags.h" |
6de9cd9a | 38 | #include "tm_p.h" |
60393bbc | 39 | #include "predict.h" |
60393bbc | 40 | #include "hard-reg-set.h" |
60393bbc AM |
41 | #include "function.h" |
42 | #include "dominance.h" | |
43 | #include "cfg.h" | |
44 | #include "cfganal.h" | |
45 | #include "basic-block.h" | |
2fb9a547 AM |
46 | #include "tree-ssa-alias.h" |
47 | #include "internal-fn.h" | |
48 | #include "gimple-expr.h" | |
49 | #include "is-a.h" | |
18f429e2 | 50 | #include "gimple.h" |
45b0be94 | 51 | #include "gimplify.h" |
5be5c238 | 52 | #include "gimple-iterator.h" |
18f429e2 | 53 | #include "gimplify-me.h" |
442b4905 AM |
54 | #include "gimple-ssa.h" |
55 | #include "tree-cfg.h" | |
56 | #include "tree-phinodes.h" | |
57 | #include "ssa-iterators.h" | |
d8a2d370 | 58 | #include "stringpool.h" |
442b4905 | 59 | #include "tree-ssanames.h" |
36566b39 PK |
60 | #include "hashtab.h" |
61 | #include "rtl.h" | |
62 | #include "statistics.h" | |
63 | #include "real.h" | |
64 | #include "fixed-value.h" | |
65 | #include "insn-config.h" | |
66 | #include "expmed.h" | |
67 | #include "dojump.h" | |
68 | #include "explow.h" | |
69 | #include "calls.h" | |
70 | #include "emit-rtl.h" | |
71 | #include "varasm.h" | |
72 | #include "stmt.h" | |
d8a2d370 | 73 | #include "expr.h" |
442b4905 | 74 | #include "tree-dfa.h" |
6de9cd9a | 75 | #include "tree-pass.h" |
6de9cd9a | 76 | #include "langhooks.h" |
a5828d1e | 77 | #include "domwalk.h" |
bfe068c3 IR |
78 | #include "cfgloop.h" |
79 | #include "tree-data-ref.h" | |
372a6eb8 | 80 | #include "gimple-pretty-print.h" |
b0710fe1 | 81 | #include "insn-codes.h" |
372a6eb8 | 82 | #include "optabs.h" |
a9e0d843 | 83 | #include "tree-scalar-evolution.h" |
421bf780 | 84 | #include "tree-inline.h" |
372a6eb8 BS |
85 | |
86 | #ifndef HAVE_conditional_move | |
87 | #define HAVE_conditional_move (0) | |
88 | #endif | |
6de9cd9a | 89 | |
372a6eb8 | 90 | static unsigned int tree_ssa_phiopt_worker (bool, bool); |
e5206274 | 91 | static bool conditional_replacement (basic_block, basic_block, |
538dd0b7 | 92 | edge, edge, gphi *, tree, tree); |
210ac0b7 AP |
93 | static int value_replacement (basic_block, basic_block, |
94 | edge, edge, gimple, tree, tree); | |
e5206274 | 95 | static bool minmax_replacement (basic_block, basic_block, |
726a989a | 96 | edge, edge, gimple, tree, tree); |
e5206274 | 97 | static bool abs_replacement (basic_block, basic_block, |
726a989a | 98 | edge, edge, gimple, tree, tree); |
a5828d1e | 99 | static bool cond_store_replacement (basic_block, basic_block, edge, edge, |
6e2830c3 | 100 | hash_set<tree> *); |
23782cc3 | 101 | static bool cond_if_else_store_replacement (basic_block, basic_block, basic_block); |
6e2830c3 | 102 | static hash_set<tree> * get_non_trapping (); |
726a989a | 103 | static void replace_phi_edge_with_variable (basic_block, edge, gimple, tree); |
372a6eb8 BS |
104 | static void hoist_adjacent_loads (basic_block, basic_block, |
105 | basic_block, basic_block); | |
106 | static bool gate_hoist_loads (void); | |
1833df5c | 107 | |
a5828d1e MM |
108 | /* This pass tries to transform conditional stores into unconditional |
109 | ones, enabling further simplifications with the simpler then and else | |
110 | blocks. In particular it replaces this: | |
111 | ||
112 | bb0: | |
113 | if (cond) goto bb2; else goto bb1; | |
114 | bb1: | |
23782cc3 | 115 | *p = RHS; |
a5828d1e MM |
116 | bb2: |
117 | ||
118 | with | |
119 | ||
120 | bb0: | |
121 | if (cond) goto bb1; else goto bb2; | |
122 | bb1: | |
123 | condtmp' = *p; | |
124 | bb2: | |
125 | condtmp = PHI <RHS, condtmp'> | |
23782cc3 | 126 | *p = condtmp; |
a5828d1e MM |
127 | |
128 | This transformation can only be done under several constraints, | |
23782cc3 JJ |
129 | documented below. It also replaces: |
130 | ||
131 | bb0: | |
132 | if (cond) goto bb2; else goto bb1; | |
133 | bb1: | |
134 | *p = RHS1; | |
135 | goto bb3; | |
136 | bb2: | |
137 | *p = RHS2; | |
138 | bb3: | |
139 | ||
140 | with | |
141 | ||
142 | bb0: | |
143 | if (cond) goto bb3; else goto bb1; | |
144 | bb1: | |
145 | bb3: | |
146 | condtmp = PHI <RHS1, RHS2> | |
147 | *p = condtmp; */ | |
a5828d1e MM |
148 | |
149 | static unsigned int | |
150 | tree_ssa_cs_elim (void) | |
151 | { | |
a9e0d843 RB |
152 | unsigned todo; |
153 | /* ??? We are not interested in loop related info, but the following | |
154 | will create it, ICEing as we didn't init loops with pre-headers. | |
155 | An interfacing issue of find_data_references_in_bb. */ | |
156 | loop_optimizer_init (LOOPS_NORMAL); | |
157 | scev_initialize (); | |
158 | todo = tree_ssa_phiopt_worker (true, false); | |
159 | scev_finalize (); | |
160 | loop_optimizer_finalize (); | |
161 | return todo; | |
a5828d1e MM |
162 | } |
163 | ||
b928d32b AP |
164 | /* Return the singleton PHI in the SEQ of PHIs for edges E0 and E1. */ |
165 | ||
538dd0b7 | 166 | static gphi * |
b928d32b AP |
167 | single_non_singleton_phi_for_edges (gimple_seq seq, edge e0, edge e1) |
168 | { | |
169 | gimple_stmt_iterator i; | |
538dd0b7 | 170 | gphi *phi = NULL; |
b928d32b | 171 | if (gimple_seq_singleton_p (seq)) |
538dd0b7 | 172 | return as_a <gphi *> (gsi_stmt (gsi_start (seq))); |
b928d32b AP |
173 | for (i = gsi_start (seq); !gsi_end_p (i); gsi_next (&i)) |
174 | { | |
538dd0b7 | 175 | gphi *p = as_a <gphi *> (gsi_stmt (i)); |
b928d32b AP |
176 | /* If the PHI arguments are equal then we can skip this PHI. */ |
177 | if (operand_equal_for_phi_arg_p (gimple_phi_arg_def (p, e0->dest_idx), | |
178 | gimple_phi_arg_def (p, e1->dest_idx))) | |
179 | continue; | |
180 | ||
181 | /* If we already have a PHI that has the two edge arguments are | |
182 | different, then return it is not a singleton for these PHIs. */ | |
183 | if (phi) | |
184 | return NULL; | |
185 | ||
186 | phi = p; | |
187 | } | |
188 | return phi; | |
189 | } | |
190 | ||
a5828d1e MM |
191 | /* The core routine of conditional store replacement and normal |
192 | phi optimizations. Both share much of the infrastructure in how | |
193 | to match applicable basic block patterns. DO_STORE_ELIM is true | |
372a6eb8 | 194 | when we want to do conditional store replacement, false otherwise. |
c9ef86a1 | 195 | DO_HOIST_LOADS is true when we want to hoist adjacent loads out |
372a6eb8 | 196 | of diamond control flow patterns, false otherwise. */ |
a5828d1e | 197 | static unsigned int |
372a6eb8 | 198 | tree_ssa_phiopt_worker (bool do_store_elim, bool do_hoist_loads) |
6de9cd9a DN |
199 | { |
200 | basic_block bb; | |
8eaa0f34 ZD |
201 | basic_block *bb_order; |
202 | unsigned n, i; | |
3e0a08d7 | 203 | bool cfgchanged = false; |
6e2830c3 | 204 | hash_set<tree> *nontrap = 0; |
a5828d1e MM |
205 | |
206 | if (do_store_elim) | |
83d5977e RG |
207 | /* Calculate the set of non-trapping memory accesses. */ |
208 | nontrap = get_non_trapping (); | |
8eaa0f34 ZD |
209 | |
210 | /* Search every basic block for COND_EXPR we may be able to optimize. | |
211 | ||
212 | We walk the blocks in order that guarantees that a block with | |
213 | a single predecessor is processed before the predecessor. | |
214 | This ensures that we collapse inner ifs before visiting the | |
215 | outer ones, and also that we do not try to visit a removed | |
216 | block. */ | |
3d9c733e | 217 | bb_order = single_pred_before_succ_order (); |
0cae8d31 | 218 | n = n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS; |
6de9cd9a | 219 | |
b8698a0f | 220 | for (i = 0; i < n; i++) |
6de9cd9a | 221 | { |
538dd0b7 DM |
222 | gimple cond_stmt; |
223 | gphi *phi; | |
80c4ed35 AP |
224 | basic_block bb1, bb2; |
225 | edge e1, e2; | |
8eaa0f34 ZD |
226 | tree arg0, arg1; |
227 | ||
228 | bb = bb_order[i]; | |
0385f644 | 229 | |
726a989a RB |
230 | cond_stmt = last_stmt (bb); |
231 | /* Check to see if the last statement is a GIMPLE_COND. */ | |
232 | if (!cond_stmt | |
233 | || gimple_code (cond_stmt) != GIMPLE_COND) | |
80c4ed35 | 234 | continue; |
0385f644 | 235 | |
80c4ed35 AP |
236 | e1 = EDGE_SUCC (bb, 0); |
237 | bb1 = e1->dest; | |
238 | e2 = EDGE_SUCC (bb, 1); | |
239 | bb2 = e2->dest; | |
0385f644 | 240 | |
80c4ed35 AP |
241 | /* We cannot do the optimization on abnormal edges. */ |
242 | if ((e1->flags & EDGE_ABNORMAL) != 0 | |
243 | || (e2->flags & EDGE_ABNORMAL) != 0) | |
244 | continue; | |
0385f644 | 245 | |
80c4ed35 | 246 | /* If either bb1's succ or bb2 or bb2's succ is non NULL. */ |
c5cbcccf | 247 | if (EDGE_COUNT (bb1->succs) == 0 |
80c4ed35 | 248 | || bb2 == NULL |
c5cbcccf | 249 | || EDGE_COUNT (bb2->succs) == 0) |
80c4ed35 | 250 | continue; |
0385f644 | 251 | |
80c4ed35 AP |
252 | /* Find the bb which is the fall through to the other. */ |
253 | if (EDGE_SUCC (bb1, 0)->dest == bb2) | |
254 | ; | |
255 | else if (EDGE_SUCC (bb2, 0)->dest == bb1) | |
256 | { | |
257 | basic_block bb_tmp = bb1; | |
258 | edge e_tmp = e1; | |
259 | bb1 = bb2; | |
260 | bb2 = bb_tmp; | |
261 | e1 = e2; | |
262 | e2 = e_tmp; | |
263 | } | |
23782cc3 JJ |
264 | else if (do_store_elim |
265 | && EDGE_SUCC (bb1, 0)->dest == EDGE_SUCC (bb2, 0)->dest) | |
266 | { | |
267 | basic_block bb3 = EDGE_SUCC (bb1, 0)->dest; | |
268 | ||
269 | if (!single_succ_p (bb1) | |
270 | || (EDGE_SUCC (bb1, 0)->flags & EDGE_FALLTHRU) == 0 | |
271 | || !single_succ_p (bb2) | |
272 | || (EDGE_SUCC (bb2, 0)->flags & EDGE_FALLTHRU) == 0 | |
273 | || EDGE_COUNT (bb3->preds) != 2) | |
274 | continue; | |
275 | if (cond_if_else_store_replacement (bb1, bb2, bb3)) | |
276 | cfgchanged = true; | |
277 | continue; | |
278 | } | |
372a6eb8 BS |
279 | else if (do_hoist_loads |
280 | && EDGE_SUCC (bb1, 0)->dest == EDGE_SUCC (bb2, 0)->dest) | |
281 | { | |
282 | basic_block bb3 = EDGE_SUCC (bb1, 0)->dest; | |
283 | ||
284 | if (!FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (cond_stmt))) | |
285 | && single_succ_p (bb1) | |
286 | && single_succ_p (bb2) | |
287 | && single_pred_p (bb1) | |
288 | && single_pred_p (bb2) | |
289 | && EDGE_COUNT (bb->succs) == 2 | |
290 | && EDGE_COUNT (bb3->preds) == 2 | |
291 | /* If one edge or the other is dominant, a conditional move | |
292 | is likely to perform worse than the well-predicted branch. */ | |
293 | && !predictable_edge_p (EDGE_SUCC (bb, 0)) | |
294 | && !predictable_edge_p (EDGE_SUCC (bb, 1))) | |
295 | hoist_adjacent_loads (bb, bb1, bb2, bb3); | |
296 | continue; | |
297 | } | |
80c4ed35 | 298 | else |
c9ef86a1 | 299 | continue; |
0385f644 | 300 | |
80c4ed35 | 301 | e1 = EDGE_SUCC (bb1, 0); |
0385f644 | 302 | |
80c4ed35 | 303 | /* Make sure that bb1 is just a fall through. */ |
3d040dbc | 304 | if (!single_succ_p (bb1) |
80c4ed35 AP |
305 | || (e1->flags & EDGE_FALLTHRU) == 0) |
306 | continue; | |
0385f644 | 307 | |
2a925431 KH |
308 | /* Also make sure that bb1 only have one predecessor and that it |
309 | is bb. */ | |
c5cbcccf ZD |
310 | if (!single_pred_p (bb1) |
311 | || single_pred (bb1) != bb) | |
80c4ed35 | 312 | continue; |
0385f644 | 313 | |
a5828d1e MM |
314 | if (do_store_elim) |
315 | { | |
316 | /* bb1 is the middle block, bb2 the join block, bb the split block, | |
317 | e1 the fallthrough edge from bb1 to bb2. We can't do the | |
318 | optimization if the join block has more than two predecessors. */ | |
319 | if (EDGE_COUNT (bb2->preds) > 2) | |
320 | continue; | |
321 | if (cond_store_replacement (bb1, bb2, e1, e2, nontrap)) | |
322 | cfgchanged = true; | |
323 | } | |
324 | else | |
325 | { | |
726a989a | 326 | gimple_seq phis = phi_nodes (bb2); |
e106efc7 | 327 | gimple_stmt_iterator gsi; |
210ac0b7 | 328 | bool candorest = true; |
b928d32b | 329 | |
210ac0b7 AP |
330 | /* Value replacement can work with more than one PHI |
331 | so try that first. */ | |
332 | for (gsi = gsi_start (phis); !gsi_end_p (gsi); gsi_next (&gsi)) | |
333 | { | |
538dd0b7 | 334 | phi = as_a <gphi *> (gsi_stmt (gsi)); |
210ac0b7 AP |
335 | arg0 = gimple_phi_arg_def (phi, e1->dest_idx); |
336 | arg1 = gimple_phi_arg_def (phi, e2->dest_idx); | |
337 | if (value_replacement (bb, bb1, e1, e2, phi, arg0, arg1) == 2) | |
338 | { | |
339 | candorest = false; | |
340 | cfgchanged = true; | |
341 | break; | |
342 | } | |
343 | } | |
a5828d1e | 344 | |
210ac0b7 AP |
345 | if (!candorest) |
346 | continue; | |
c9ef86a1 | 347 | |
b928d32b | 348 | phi = single_non_singleton_phi_for_edges (phis, e1, e2); |
e106efc7 | 349 | if (!phi) |
a5828d1e MM |
350 | continue; |
351 | ||
726a989a RB |
352 | arg0 = gimple_phi_arg_def (phi, e1->dest_idx); |
353 | arg1 = gimple_phi_arg_def (phi, e2->dest_idx); | |
a5828d1e MM |
354 | |
355 | /* Something is wrong if we cannot find the arguments in the PHI | |
356 | node. */ | |
357 | gcc_assert (arg0 != NULL && arg1 != NULL); | |
358 | ||
359 | /* Do the replacement of conditional if it can be done. */ | |
360 | if (conditional_replacement (bb, bb1, e1, e2, phi, arg0, arg1)) | |
361 | cfgchanged = true; | |
a5828d1e MM |
362 | else if (abs_replacement (bb, bb1, e1, e2, phi, arg0, arg1)) |
363 | cfgchanged = true; | |
364 | else if (minmax_replacement (bb, bb1, e1, e2, phi, arg0, arg1)) | |
365 | cfgchanged = true; | |
366 | } | |
8eaa0f34 ZD |
367 | } |
368 | ||
369 | free (bb_order); | |
b8698a0f | 370 | |
a5828d1e | 371 | if (do_store_elim) |
6e2830c3 | 372 | delete nontrap; |
a5828d1e MM |
373 | /* If the CFG has changed, we should cleanup the CFG. */ |
374 | if (cfgchanged && do_store_elim) | |
375 | { | |
376 | /* In cond-store replacement we have added some loads on edges | |
377 | and new VOPS (as we moved the store, and created a load). */ | |
726a989a | 378 | gsi_commit_edge_inserts (); |
a5828d1e MM |
379 | return TODO_cleanup_cfg | TODO_update_ssa_only_virtuals; |
380 | } | |
381 | else if (cfgchanged) | |
382 | return TODO_cleanup_cfg; | |
383 | return 0; | |
8eaa0f34 ZD |
384 | } |
385 | ||
696e78bf | 386 | /* Replace PHI node element whose edge is E in block BB with variable NEW. |
80c4ed35 | 387 | Remove the edge from COND_BLOCK which does not lead to BB (COND_BLOCK |
1833df5c JL |
388 | is known to have two edges, one of which must reach BB). */ |
389 | ||
390 | static void | |
e5206274 | 391 | replace_phi_edge_with_variable (basic_block cond_block, |
726a989a | 392 | edge e, gimple phi, tree new_tree) |
1833df5c | 393 | { |
726a989a | 394 | basic_block bb = gimple_bb (phi); |
8a807136 | 395 | basic_block block_to_remove; |
726a989a | 396 | gimple_stmt_iterator gsi; |
80c4ed35 | 397 | |
0385f644 | 398 | /* Change the PHI argument to new. */ |
c22940cd | 399 | SET_USE (PHI_ARG_DEF_PTR (phi, e->dest_idx), new_tree); |
8a807136 | 400 | |
8a807136 | 401 | /* Remove the empty basic block. */ |
628f6a4e | 402 | if (EDGE_SUCC (cond_block, 0)->dest == bb) |
1833df5c | 403 | { |
628f6a4e BE |
404 | EDGE_SUCC (cond_block, 0)->flags |= EDGE_FALLTHRU; |
405 | EDGE_SUCC (cond_block, 0)->flags &= ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE); | |
afc970a4 JH |
406 | EDGE_SUCC (cond_block, 0)->probability = REG_BR_PROB_BASE; |
407 | EDGE_SUCC (cond_block, 0)->count += EDGE_SUCC (cond_block, 1)->count; | |
8a807136 | 408 | |
628f6a4e | 409 | block_to_remove = EDGE_SUCC (cond_block, 1)->dest; |
1833df5c JL |
410 | } |
411 | else | |
412 | { | |
628f6a4e BE |
413 | EDGE_SUCC (cond_block, 1)->flags |= EDGE_FALLTHRU; |
414 | EDGE_SUCC (cond_block, 1)->flags | |
1833df5c | 415 | &= ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE); |
afc970a4 JH |
416 | EDGE_SUCC (cond_block, 1)->probability = REG_BR_PROB_BASE; |
417 | EDGE_SUCC (cond_block, 1)->count += EDGE_SUCC (cond_block, 0)->count; | |
8a807136 | 418 | |
628f6a4e | 419 | block_to_remove = EDGE_SUCC (cond_block, 0)->dest; |
1833df5c | 420 | } |
8a807136 | 421 | delete_basic_block (block_to_remove); |
0385f644 | 422 | |
1833df5c | 423 | /* Eliminate the COND_EXPR at the end of COND_BLOCK. */ |
726a989a RB |
424 | gsi = gsi_last_bb (cond_block); |
425 | gsi_remove (&gsi, true); | |
0385f644 | 426 | |
1833df5c JL |
427 | if (dump_file && (dump_flags & TDF_DETAILS)) |
428 | fprintf (dump_file, | |
429 | "COND_EXPR in block %d and PHI in block %d converted to straightline code.\n", | |
430 | cond_block->index, | |
431 | bb->index); | |
432 | } | |
433 | ||
434 | /* The function conditional_replacement does the main work of doing the | |
435 | conditional replacement. Return true if the replacement is done. | |
436 | Otherwise return false. | |
437 | BB is the basic block where the replacement is going to be done on. ARG0 | |
471854f8 | 438 | is argument 0 from PHI. Likewise for ARG1. */ |
1833df5c JL |
439 | |
440 | static bool | |
80c4ed35 | 441 | conditional_replacement (basic_block cond_bb, basic_block middle_bb, |
538dd0b7 | 442 | edge e0, edge e1, gphi *phi, |
80c4ed35 | 443 | tree arg0, tree arg1) |
1833df5c JL |
444 | { |
445 | tree result; | |
538dd0b7 DM |
446 | gimple stmt; |
447 | gassign *new_stmt; | |
726a989a RB |
448 | tree cond; |
449 | gimple_stmt_iterator gsi; | |
1833df5c | 450 | edge true_edge, false_edge; |
726a989a | 451 | tree new_var, new_var2; |
809c929c | 452 | bool neg; |
1833df5c | 453 | |
550386ad | 454 | /* FIXME: Gimplification of complex type is too hard for now. */ |
5dcf6b7f JJ |
455 | /* We aren't prepared to handle vectors either (and it is a question |
456 | if it would be worthwhile anyway). */ | |
457 | if (!(INTEGRAL_TYPE_P (TREE_TYPE (arg0)) | |
458 | || POINTER_TYPE_P (TREE_TYPE (arg0))) | |
459 | || !(INTEGRAL_TYPE_P (TREE_TYPE (arg1)) | |
460 | || POINTER_TYPE_P (TREE_TYPE (arg1)))) | |
550386ad AP |
461 | return false; |
462 | ||
809c929c PB |
463 | /* The PHI arguments have the constants 0 and 1, or 0 and -1, then |
464 | convert it to the conditional. */ | |
1833df5c JL |
465 | if ((integer_zerop (arg0) && integer_onep (arg1)) |
466 | || (integer_zerop (arg1) && integer_onep (arg0))) | |
809c929c PB |
467 | neg = false; |
468 | else if ((integer_zerop (arg0) && integer_all_onesp (arg1)) | |
469 | || (integer_zerop (arg1) && integer_all_onesp (arg0))) | |
470 | neg = true; | |
1833df5c JL |
471 | else |
472 | return false; | |
0385f644 | 473 | |
80c4ed35 | 474 | if (!empty_block_p (middle_bb)) |
1833df5c | 475 | return false; |
0385f644 | 476 | |
726a989a | 477 | /* At this point we know we have a GIMPLE_COND with two successors. |
14886ab7 JL |
478 | One successor is BB, the other successor is an empty block which |
479 | falls through into BB. | |
0385f644 | 480 | |
14886ab7 | 481 | There is a single PHI node at the join point (BB) and its arguments |
809c929c | 482 | are constants (0, 1) or (0, -1). |
0385f644 | 483 | |
14886ab7 | 484 | So, given the condition COND, and the two PHI arguments, we can |
0385f644 KH |
485 | rewrite this PHI into non-branching code: |
486 | ||
14886ab7 | 487 | dest = (COND) or dest = COND' |
0385f644 | 488 | |
14886ab7 JL |
489 | We use the condition as-is if the argument associated with the |
490 | true edge has the value one or the argument associated with the | |
491 | false edge as the value zero. Note that those conditions are not | |
726a989a | 492 | the same since only one of the outgoing edges from the GIMPLE_COND |
14886ab7 | 493 | will directly reach BB and thus be associated with an argument. */ |
571325db | 494 | |
726a989a RB |
495 | stmt = last_stmt (cond_bb); |
496 | result = PHI_RESULT (phi); | |
800dd123 | 497 | |
726a989a RB |
498 | /* To handle special cases like floating point comparison, it is easier and |
499 | less error-prone to build a tree and gimplify it on the fly though it is | |
500 | less efficient. */ | |
f8ecf734 RG |
501 | cond = fold_build2_loc (gimple_location (stmt), |
502 | gimple_cond_code (stmt), boolean_type_node, | |
503 | gimple_cond_lhs (stmt), gimple_cond_rhs (stmt)); | |
6de9cd9a | 504 | |
726a989a RB |
505 | /* We need to know which is the true edge and which is the false |
506 | edge so that we know when to invert the condition below. */ | |
507 | extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge); | |
508 | if ((e0 == true_edge && integer_zerop (arg0)) | |
809c929c | 509 | || (e0 == false_edge && !integer_zerop (arg0)) |
726a989a | 510 | || (e1 == true_edge && integer_zerop (arg1)) |
809c929c | 511 | || (e1 == false_edge && !integer_zerop (arg1))) |
f8ecf734 | 512 | cond = fold_build1_loc (gimple_location (stmt), |
809c929c PB |
513 | TRUTH_NOT_EXPR, TREE_TYPE (cond), cond); |
514 | ||
515 | if (neg) | |
516 | { | |
517 | cond = fold_convert_loc (gimple_location (stmt), | |
518 | TREE_TYPE (result), cond); | |
519 | cond = fold_build1_loc (gimple_location (stmt), | |
520 | NEGATE_EXPR, TREE_TYPE (cond), cond); | |
521 | } | |
726a989a RB |
522 | |
523 | /* Insert our new statements at the end of conditional block before the | |
524 | COND_STMT. */ | |
525 | gsi = gsi_for_stmt (stmt); | |
526 | new_var = force_gimple_operand_gsi (&gsi, cond, true, NULL, true, | |
527 | GSI_SAME_STMT); | |
528 | ||
529 | if (!useless_type_conversion_p (TREE_TYPE (result), TREE_TYPE (new_var))) | |
530 | { | |
f5045c96 AM |
531 | source_location locus_0, locus_1; |
532 | ||
b731b390 | 533 | new_var2 = make_ssa_name (TREE_TYPE (result)); |
0d0e4a03 | 534 | new_stmt = gimple_build_assign (new_var2, CONVERT_EXPR, new_var); |
726a989a RB |
535 | gsi_insert_before (&gsi, new_stmt, GSI_SAME_STMT); |
536 | new_var = new_var2; | |
f5045c96 AM |
537 | |
538 | /* Set the locus to the first argument, unless is doesn't have one. */ | |
539 | locus_0 = gimple_phi_arg_location (phi, 0); | |
540 | locus_1 = gimple_phi_arg_location (phi, 1); | |
541 | if (locus_0 == UNKNOWN_LOCATION) | |
542 | locus_0 = locus_1; | |
543 | gimple_set_location (new_stmt, locus_0); | |
6de9cd9a | 544 | } |
0385f644 | 545 | |
726a989a | 546 | replace_phi_edge_with_variable (cond_bb, e1, phi, new_var); |
1833df5c | 547 | |
6de9cd9a DN |
548 | /* Note that we optimized this PHI. */ |
549 | return true; | |
550 | } | |
551 | ||
98dd3b73 RG |
552 | /* Update *ARG which is defined in STMT so that it contains the |
553 | computed value if that seems profitable. Return true if the | |
554 | statement is made dead by that rewriting. */ | |
555 | ||
556 | static bool | |
557 | jump_function_from_stmt (tree *arg, gimple stmt) | |
558 | { | |
559 | enum tree_code code = gimple_assign_rhs_code (stmt); | |
560 | if (code == ADDR_EXPR) | |
561 | { | |
562 | /* For arg = &p->i transform it to p, if possible. */ | |
563 | tree rhs1 = gimple_assign_rhs1 (stmt); | |
564 | HOST_WIDE_INT offset; | |
565 | tree tem = get_addr_base_and_unit_offset (TREE_OPERAND (rhs1, 0), | |
566 | &offset); | |
567 | if (tem | |
568 | && TREE_CODE (tem) == MEM_REF | |
807e902e | 569 | && (mem_ref_offset (tem) + offset) == 0) |
98dd3b73 RG |
570 | { |
571 | *arg = TREE_OPERAND (tem, 0); | |
572 | return true; | |
573 | } | |
574 | } | |
575 | /* TODO: Much like IPA-CP jump-functions we want to handle constant | |
576 | additions symbolically here, and we'd need to update the comparison | |
577 | code that compares the arg + cst tuples in our caller. For now the | |
578 | code above exactly handles the VEC_BASE pattern from vec.h. */ | |
579 | return false; | |
580 | } | |
581 | ||
c9ef86a1 ZC |
582 | /* RHS is a source argument in a BIT_AND_EXPR which feeds a conditional |
583 | of the form SSA_NAME NE 0. | |
584 | ||
585 | If RHS is fed by a simple EQ_EXPR comparison of two values, see if | |
586 | the two input values of the EQ_EXPR match arg0 and arg1. | |
587 | ||
588 | If so update *code and return TRUE. Otherwise return FALSE. */ | |
589 | ||
590 | static bool | |
591 | rhs_is_fed_for_value_replacement (const_tree arg0, const_tree arg1, | |
592 | enum tree_code *code, const_tree rhs) | |
593 | { | |
594 | /* Obviously if RHS is not an SSA_NAME, we can't look at the defining | |
595 | statement. */ | |
596 | if (TREE_CODE (rhs) == SSA_NAME) | |
597 | { | |
598 | gimple def1 = SSA_NAME_DEF_STMT (rhs); | |
599 | ||
600 | /* Verify the defining statement has an EQ_EXPR on the RHS. */ | |
601 | if (is_gimple_assign (def1) && gimple_assign_rhs_code (def1) == EQ_EXPR) | |
602 | { | |
603 | /* Finally verify the source operands of the EQ_EXPR are equal | |
604 | to arg0 and arg1. */ | |
605 | tree op0 = gimple_assign_rhs1 (def1); | |
606 | tree op1 = gimple_assign_rhs2 (def1); | |
607 | if ((operand_equal_for_phi_arg_p (arg0, op0) | |
608 | && operand_equal_for_phi_arg_p (arg1, op1)) | |
609 | || (operand_equal_for_phi_arg_p (arg0, op1) | |
610 | && operand_equal_for_phi_arg_p (arg1, op0))) | |
611 | { | |
612 | /* We will perform the optimization. */ | |
613 | *code = gimple_assign_rhs_code (def1); | |
614 | return true; | |
615 | } | |
616 | } | |
617 | } | |
618 | return false; | |
619 | } | |
620 | ||
621 | /* Return TRUE if arg0/arg1 are equal to the rhs/lhs or lhs/rhs of COND. | |
622 | ||
623 | Also return TRUE if arg0/arg1 are equal to the source arguments of a | |
624 | an EQ comparison feeding a BIT_AND_EXPR which feeds COND. | |
625 | ||
626 | Return FALSE otherwise. */ | |
627 | ||
628 | static bool | |
629 | operand_equal_for_value_replacement (const_tree arg0, const_tree arg1, | |
630 | enum tree_code *code, gimple cond) | |
631 | { | |
632 | gimple def; | |
633 | tree lhs = gimple_cond_lhs (cond); | |
634 | tree rhs = gimple_cond_rhs (cond); | |
635 | ||
636 | if ((operand_equal_for_phi_arg_p (arg0, lhs) | |
637 | && operand_equal_for_phi_arg_p (arg1, rhs)) | |
638 | || (operand_equal_for_phi_arg_p (arg1, lhs) | |
639 | && operand_equal_for_phi_arg_p (arg0, rhs))) | |
640 | return true; | |
641 | ||
642 | /* Now handle more complex case where we have an EQ comparison | |
643 | which feeds a BIT_AND_EXPR which feeds COND. | |
644 | ||
645 | First verify that COND is of the form SSA_NAME NE 0. */ | |
646 | if (*code != NE_EXPR || !integer_zerop (rhs) | |
647 | || TREE_CODE (lhs) != SSA_NAME) | |
648 | return false; | |
649 | ||
650 | /* Now ensure that SSA_NAME is set by a BIT_AND_EXPR. */ | |
651 | def = SSA_NAME_DEF_STMT (lhs); | |
652 | if (!is_gimple_assign (def) || gimple_assign_rhs_code (def) != BIT_AND_EXPR) | |
653 | return false; | |
654 | ||
655 | /* Now verify arg0/arg1 correspond to the source arguments of an | |
656 | EQ comparison feeding the BIT_AND_EXPR. */ | |
657 | ||
658 | tree tmp = gimple_assign_rhs1 (def); | |
659 | if (rhs_is_fed_for_value_replacement (arg0, arg1, code, tmp)) | |
660 | return true; | |
661 | ||
662 | tmp = gimple_assign_rhs2 (def); | |
663 | if (rhs_is_fed_for_value_replacement (arg0, arg1, code, tmp)) | |
664 | return true; | |
665 | ||
666 | return false; | |
667 | } | |
668 | ||
421bf780 MG |
669 | /* Returns true if ARG is a neutral element for operation CODE |
670 | on the RIGHT side. */ | |
671 | ||
672 | static bool | |
673 | neutral_element_p (tree_code code, tree arg, bool right) | |
674 | { | |
675 | switch (code) | |
676 | { | |
677 | case PLUS_EXPR: | |
678 | case BIT_IOR_EXPR: | |
679 | case BIT_XOR_EXPR: | |
680 | return integer_zerop (arg); | |
681 | ||
682 | case LROTATE_EXPR: | |
683 | case RROTATE_EXPR: | |
684 | case LSHIFT_EXPR: | |
685 | case RSHIFT_EXPR: | |
686 | case MINUS_EXPR: | |
687 | case POINTER_PLUS_EXPR: | |
688 | return right && integer_zerop (arg); | |
689 | ||
690 | case MULT_EXPR: | |
691 | return integer_onep (arg); | |
692 | ||
693 | case TRUNC_DIV_EXPR: | |
694 | case CEIL_DIV_EXPR: | |
695 | case FLOOR_DIV_EXPR: | |
696 | case ROUND_DIV_EXPR: | |
697 | case EXACT_DIV_EXPR: | |
698 | return right && integer_onep (arg); | |
699 | ||
700 | case BIT_AND_EXPR: | |
701 | return integer_all_onesp (arg); | |
702 | ||
703 | default: | |
704 | return false; | |
705 | } | |
706 | } | |
707 | ||
708 | /* Returns true if ARG is an absorbing element for operation CODE. */ | |
709 | ||
710 | static bool | |
711 | absorbing_element_p (tree_code code, tree arg) | |
712 | { | |
713 | switch (code) | |
714 | { | |
715 | case BIT_IOR_EXPR: | |
716 | return integer_all_onesp (arg); | |
717 | ||
718 | case MULT_EXPR: | |
719 | case BIT_AND_EXPR: | |
720 | return integer_zerop (arg); | |
721 | ||
722 | default: | |
723 | return false; | |
724 | } | |
725 | } | |
726 | ||
3a3f4da9 | 727 | /* The function value_replacement does the main work of doing the value |
210ac0b7 AP |
728 | replacement. Return non-zero if the replacement is done. Otherwise return |
729 | 0. If we remove the middle basic block, return 2. | |
3a3f4da9 | 730 | BB is the basic block where the replacement is going to be done on. ARG0 |
471854f8 | 731 | is argument 0 from the PHI. Likewise for ARG1. */ |
3a3f4da9 | 732 | |
210ac0b7 | 733 | static int |
80c4ed35 | 734 | value_replacement (basic_block cond_bb, basic_block middle_bb, |
726a989a | 735 | edge e0, edge e1, gimple phi, |
80c4ed35 | 736 | tree arg0, tree arg1) |
3a3f4da9 | 737 | { |
98dd3b73 | 738 | gimple_stmt_iterator gsi; |
726a989a | 739 | gimple cond; |
3a3f4da9 | 740 | edge true_edge, false_edge; |
726a989a | 741 | enum tree_code code; |
210ac0b7 | 742 | bool emtpy_or_with_defined_p = true; |
3a3f4da9 AP |
743 | |
744 | /* If the type says honor signed zeros we cannot do this | |
471854f8 | 745 | optimization. */ |
3d3dbadd | 746 | if (HONOR_SIGNED_ZEROS (arg1)) |
210ac0b7 | 747 | return 0; |
3a3f4da9 | 748 | |
210ac0b7 AP |
749 | /* If there is a statement in MIDDLE_BB that defines one of the PHI |
750 | arguments, then adjust arg0 or arg1. */ | |
421bf780 | 751 | gsi = gsi_start_nondebug_after_labels_bb (middle_bb); |
210ac0b7 | 752 | while (!gsi_end_p (gsi)) |
98dd3b73 | 753 | { |
210ac0b7 AP |
754 | gimple stmt = gsi_stmt (gsi); |
755 | tree lhs; | |
756 | gsi_next_nondebug (&gsi); | |
757 | if (!is_gimple_assign (stmt)) | |
98dd3b73 | 758 | { |
210ac0b7 AP |
759 | emtpy_or_with_defined_p = false; |
760 | continue; | |
98dd3b73 | 761 | } |
210ac0b7 AP |
762 | /* Now try to adjust arg0 or arg1 according to the computation |
763 | in the statement. */ | |
764 | lhs = gimple_assign_lhs (stmt); | |
765 | if (!(lhs == arg0 | |
766 | && jump_function_from_stmt (&arg0, stmt)) | |
767 | || (lhs == arg1 | |
768 | && jump_function_from_stmt (&arg1, stmt))) | |
769 | emtpy_or_with_defined_p = false; | |
98dd3b73 | 770 | } |
3a3f4da9 | 771 | |
726a989a RB |
772 | cond = last_stmt (cond_bb); |
773 | code = gimple_cond_code (cond); | |
3a3f4da9 AP |
774 | |
775 | /* This transformation is only valid for equality comparisons. */ | |
726a989a | 776 | if (code != NE_EXPR && code != EQ_EXPR) |
210ac0b7 | 777 | return 0; |
3a3f4da9 AP |
778 | |
779 | /* We need to know which is the true edge and which is the false | |
780 | edge so that we know if have abs or negative abs. */ | |
80c4ed35 | 781 | extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge); |
3a3f4da9 AP |
782 | |
783 | /* At this point we know we have a COND_EXPR with two successors. | |
784 | One successor is BB, the other successor is an empty block which | |
785 | falls through into BB. | |
786 | ||
787 | The condition for the COND_EXPR is known to be NE_EXPR or EQ_EXPR. | |
788 | ||
789 | There is a single PHI node at the join point (BB) with two arguments. | |
790 | ||
791 | We now need to verify that the two arguments in the PHI node match | |
792 | the two arguments to the equality comparison. */ | |
0385f644 | 793 | |
c9ef86a1 | 794 | if (operand_equal_for_value_replacement (arg0, arg1, &code, cond)) |
3a3f4da9 AP |
795 | { |
796 | edge e; | |
797 | tree arg; | |
798 | ||
84c672b9 JL |
799 | /* For NE_EXPR, we want to build an assignment result = arg where |
800 | arg is the PHI argument associated with the true edge. For | |
801 | EQ_EXPR we want the PHI argument associated with the false edge. */ | |
726a989a | 802 | e = (code == NE_EXPR ? true_edge : false_edge); |
84c672b9 JL |
803 | |
804 | /* Unfortunately, E may not reach BB (it may instead have gone to | |
805 | OTHER_BLOCK). If that is the case, then we want the single outgoing | |
806 | edge from OTHER_BLOCK which reaches BB and represents the desired | |
807 | path from COND_BLOCK. */ | |
80c4ed35 | 808 | if (e->dest == middle_bb) |
c5cbcccf | 809 | e = single_succ_edge (e->dest); |
84c672b9 JL |
810 | |
811 | /* Now we know the incoming edge to BB that has the argument for the | |
812 | RHS of our new assignment statement. */ | |
80c4ed35 | 813 | if (e0 == e) |
3a3f4da9 AP |
814 | arg = arg0; |
815 | else | |
816 | arg = arg1; | |
817 | ||
210ac0b7 | 818 | /* If the middle basic block was empty or is defining the |
b928d32b AP |
819 | PHI arguments and this is a single phi where the args are different |
820 | for the edges e0 and e1 then we can remove the middle basic block. */ | |
210ac0b7 | 821 | if (emtpy_or_with_defined_p |
b928d32b | 822 | && single_non_singleton_phi_for_edges (phi_nodes (gimple_bb (phi)), |
1a6230a8 | 823 | e0, e1) == phi) |
210ac0b7 AP |
824 | { |
825 | replace_phi_edge_with_variable (cond_bb, e1, phi, arg); | |
826 | /* Note that we optimized this PHI. */ | |
827 | return 2; | |
828 | } | |
829 | else | |
830 | { | |
831 | /* Replace the PHI arguments with arg. */ | |
832 | SET_PHI_ARG_DEF (phi, e0->dest_idx, arg); | |
833 | SET_PHI_ARG_DEF (phi, e1->dest_idx, arg); | |
834 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
835 | { | |
836 | fprintf (dump_file, "PHI "); | |
837 | print_generic_expr (dump_file, gimple_phi_result (phi), 0); | |
b928d32b AP |
838 | fprintf (dump_file, " reduced for COND_EXPR in block %d to ", |
839 | cond_bb->index); | |
210ac0b7 AP |
840 | print_generic_expr (dump_file, arg, 0); |
841 | fprintf (dump_file, ".\n"); | |
842 | } | |
843 | return 1; | |
844 | } | |
3a3f4da9 | 845 | |
3a3f4da9 | 846 | } |
421bf780 MG |
847 | |
848 | /* Now optimize (x != 0) ? x + y : y to just y. | |
849 | The following condition is too restrictive, there can easily be another | |
850 | stmt in middle_bb, for instance a CONVERT_EXPR for the second argument. */ | |
851 | gimple assign = last_and_only_stmt (middle_bb); | |
852 | if (!assign || gimple_code (assign) != GIMPLE_ASSIGN | |
853 | || gimple_assign_rhs_class (assign) != GIMPLE_BINARY_RHS | |
854 | || (!INTEGRAL_TYPE_P (TREE_TYPE (arg0)) | |
855 | && !POINTER_TYPE_P (TREE_TYPE (arg0)))) | |
856 | return 0; | |
857 | ||
ca73a1f7 MG |
858 | /* Punt if there are (degenerate) PHIs in middle_bb, there should not be. */ |
859 | if (!gimple_seq_empty_p (phi_nodes (middle_bb))) | |
860 | return 0; | |
861 | ||
87a34442 MG |
862 | /* Only transform if it removes the condition. */ |
863 | if (!single_non_singleton_phi_for_edges (phi_nodes (gimple_bb (phi)), e0, e1)) | |
864 | return 0; | |
865 | ||
421bf780 MG |
866 | /* Size-wise, this is always profitable. */ |
867 | if (optimize_bb_for_speed_p (cond_bb) | |
868 | /* The special case is useless if it has a low probability. */ | |
869 | && profile_status_for_fn (cfun) != PROFILE_ABSENT | |
870 | && EDGE_PRED (middle_bb, 0)->probability < PROB_EVEN | |
871 | /* If assign is cheap, there is no point avoiding it. */ | |
872 | && estimate_num_insns (assign, &eni_time_weights) | |
873 | >= 3 * estimate_num_insns (cond, &eni_time_weights)) | |
874 | return 0; | |
875 | ||
876 | tree lhs = gimple_assign_lhs (assign); | |
877 | tree rhs1 = gimple_assign_rhs1 (assign); | |
878 | tree rhs2 = gimple_assign_rhs2 (assign); | |
879 | enum tree_code code_def = gimple_assign_rhs_code (assign); | |
880 | tree cond_lhs = gimple_cond_lhs (cond); | |
881 | tree cond_rhs = gimple_cond_rhs (cond); | |
882 | ||
883 | if (((code == NE_EXPR && e1 == false_edge) | |
884 | || (code == EQ_EXPR && e1 == true_edge)) | |
885 | && arg0 == lhs | |
886 | && ((arg1 == rhs1 | |
887 | && operand_equal_for_phi_arg_p (rhs2, cond_lhs) | |
888 | && neutral_element_p (code_def, cond_rhs, true)) | |
889 | || (arg1 == rhs2 | |
890 | && operand_equal_for_phi_arg_p (rhs1, cond_lhs) | |
891 | && neutral_element_p (code_def, cond_rhs, false)) | |
892 | || (operand_equal_for_phi_arg_p (arg1, cond_rhs) | |
893 | && (operand_equal_for_phi_arg_p (rhs2, cond_lhs) | |
894 | || operand_equal_for_phi_arg_p (rhs1, cond_lhs)) | |
895 | && absorbing_element_p (code_def, cond_rhs)))) | |
896 | { | |
897 | gsi = gsi_for_stmt (cond); | |
f7a0790f JJ |
898 | if (INTEGRAL_TYPE_P (TREE_TYPE (lhs))) |
899 | { | |
900 | /* Moving ASSIGN might change VR of lhs, e.g. when moving u_6 | |
901 | def-stmt in: | |
902 | if (n_5 != 0) | |
903 | goto <bb 3>; | |
904 | else | |
905 | goto <bb 4>; | |
906 | ||
907 | <bb 3>: | |
908 | # RANGE [0, 4294967294] | |
909 | u_6 = n_5 + 4294967295; | |
910 | ||
911 | <bb 4>: | |
912 | # u_3 = PHI <u_6(3), 4294967295(2)> */ | |
913 | SSA_NAME_RANGE_INFO (lhs) = NULL; | |
914 | SSA_NAME_ANTI_RANGE_P (lhs) = 0; | |
915 | /* If available, we can use VR of phi result at least. */ | |
916 | tree phires = gimple_phi_result (phi); | |
917 | struct range_info_def *phires_range_info | |
918 | = SSA_NAME_RANGE_INFO (phires); | |
919 | if (phires_range_info) | |
920 | duplicate_ssa_name_range_info (lhs, SSA_NAME_RANGE_TYPE (phires), | |
921 | phires_range_info); | |
922 | } | |
421bf780 MG |
923 | gimple_stmt_iterator gsi_from = gsi_for_stmt (assign); |
924 | gsi_move_before (&gsi_from, &gsi); | |
925 | replace_phi_edge_with_variable (cond_bb, e1, phi, lhs); | |
926 | return 2; | |
927 | } | |
928 | ||
210ac0b7 | 929 | return 0; |
3a3f4da9 AP |
930 | } |
931 | ||
8eaa0f34 ZD |
932 | /* The function minmax_replacement does the main work of doing the minmax |
933 | replacement. Return true if the replacement is done. Otherwise return | |
934 | false. | |
935 | BB is the basic block where the replacement is going to be done on. ARG0 | |
936 | is argument 0 from the PHI. Likewise for ARG1. */ | |
937 | ||
938 | static bool | |
939 | minmax_replacement (basic_block cond_bb, basic_block middle_bb, | |
726a989a | 940 | edge e0, edge e1, gimple phi, |
8eaa0f34 ZD |
941 | tree arg0, tree arg1) |
942 | { | |
943 | tree result, type; | |
538dd0b7 DM |
944 | gcond *cond; |
945 | gassign *new_stmt; | |
8eaa0f34 ZD |
946 | edge true_edge, false_edge; |
947 | enum tree_code cmp, minmax, ass_code; | |
948 | tree smaller, larger, arg_true, arg_false; | |
726a989a | 949 | gimple_stmt_iterator gsi, gsi_from; |
8eaa0f34 ZD |
950 | |
951 | type = TREE_TYPE (PHI_RESULT (phi)); | |
952 | ||
953 | /* The optimization may be unsafe due to NaNs. */ | |
1b457aa4 | 954 | if (HONOR_NANS (type)) |
8eaa0f34 ZD |
955 | return false; |
956 | ||
538dd0b7 | 957 | cond = as_a <gcond *> (last_stmt (cond_bb)); |
726a989a | 958 | cmp = gimple_cond_code (cond); |
8eaa0f34 ZD |
959 | |
960 | /* This transformation is only valid for order comparisons. Record which | |
961 | operand is smaller/larger if the result of the comparison is true. */ | |
962 | if (cmp == LT_EXPR || cmp == LE_EXPR) | |
963 | { | |
726a989a RB |
964 | smaller = gimple_cond_lhs (cond); |
965 | larger = gimple_cond_rhs (cond); | |
8eaa0f34 ZD |
966 | } |
967 | else if (cmp == GT_EXPR || cmp == GE_EXPR) | |
968 | { | |
726a989a RB |
969 | smaller = gimple_cond_rhs (cond); |
970 | larger = gimple_cond_lhs (cond); | |
8eaa0f34 ZD |
971 | } |
972 | else | |
973 | return false; | |
974 | ||
975 | /* We need to know which is the true edge and which is the false | |
976 | edge so that we know if have abs or negative abs. */ | |
977 | extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge); | |
978 | ||
979 | /* Forward the edges over the middle basic block. */ | |
980 | if (true_edge->dest == middle_bb) | |
981 | true_edge = EDGE_SUCC (true_edge->dest, 0); | |
982 | if (false_edge->dest == middle_bb) | |
983 | false_edge = EDGE_SUCC (false_edge->dest, 0); | |
984 | ||
985 | if (true_edge == e0) | |
986 | { | |
987 | gcc_assert (false_edge == e1); | |
988 | arg_true = arg0; | |
989 | arg_false = arg1; | |
990 | } | |
991 | else | |
992 | { | |
993 | gcc_assert (false_edge == e0); | |
994 | gcc_assert (true_edge == e1); | |
995 | arg_true = arg1; | |
996 | arg_false = arg0; | |
997 | } | |
998 | ||
999 | if (empty_block_p (middle_bb)) | |
1000 | { | |
1001 | if (operand_equal_for_phi_arg_p (arg_true, smaller) | |
1002 | && operand_equal_for_phi_arg_p (arg_false, larger)) | |
1003 | { | |
1004 | /* Case | |
b8698a0f | 1005 | |
8eaa0f34 ZD |
1006 | if (smaller < larger) |
1007 | rslt = smaller; | |
1008 | else | |
1009 | rslt = larger; */ | |
1010 | minmax = MIN_EXPR; | |
1011 | } | |
1012 | else if (operand_equal_for_phi_arg_p (arg_false, smaller) | |
1013 | && operand_equal_for_phi_arg_p (arg_true, larger)) | |
1014 | minmax = MAX_EXPR; | |
1015 | else | |
1016 | return false; | |
1017 | } | |
1018 | else | |
1019 | { | |
1020 | /* Recognize the following case, assuming d <= u: | |
1021 | ||
1022 | if (a <= u) | |
1023 | b = MAX (a, d); | |
1024 | x = PHI <b, u> | |
1025 | ||
1026 | This is equivalent to | |
1027 | ||
1028 | b = MAX (a, d); | |
1029 | x = MIN (b, u); */ | |
1030 | ||
726a989a RB |
1031 | gimple assign = last_and_only_stmt (middle_bb); |
1032 | tree lhs, op0, op1, bound; | |
8eaa0f34 ZD |
1033 | |
1034 | if (!assign | |
726a989a | 1035 | || gimple_code (assign) != GIMPLE_ASSIGN) |
8eaa0f34 ZD |
1036 | return false; |
1037 | ||
726a989a RB |
1038 | lhs = gimple_assign_lhs (assign); |
1039 | ass_code = gimple_assign_rhs_code (assign); | |
8eaa0f34 ZD |
1040 | if (ass_code != MAX_EXPR && ass_code != MIN_EXPR) |
1041 | return false; | |
726a989a RB |
1042 | op0 = gimple_assign_rhs1 (assign); |
1043 | op1 = gimple_assign_rhs2 (assign); | |
8eaa0f34 ZD |
1044 | |
1045 | if (true_edge->src == middle_bb) | |
1046 | { | |
1047 | /* We got here if the condition is true, i.e., SMALLER < LARGER. */ | |
1048 | if (!operand_equal_for_phi_arg_p (lhs, arg_true)) | |
1049 | return false; | |
1050 | ||
1051 | if (operand_equal_for_phi_arg_p (arg_false, larger)) | |
1052 | { | |
1053 | /* Case | |
1054 | ||
1055 | if (smaller < larger) | |
1056 | { | |
1057 | r' = MAX_EXPR (smaller, bound) | |
1058 | } | |
1059 | r = PHI <r', larger> --> to be turned to MIN_EXPR. */ | |
1060 | if (ass_code != MAX_EXPR) | |
1061 | return false; | |
1062 | ||
1063 | minmax = MIN_EXPR; | |
1064 | if (operand_equal_for_phi_arg_p (op0, smaller)) | |
1065 | bound = op1; | |
1066 | else if (operand_equal_for_phi_arg_p (op1, smaller)) | |
1067 | bound = op0; | |
1068 | else | |
1069 | return false; | |
1070 | ||
1071 | /* We need BOUND <= LARGER. */ | |
987b67bc KH |
1072 | if (!integer_nonzerop (fold_build2 (LE_EXPR, boolean_type_node, |
1073 | bound, larger))) | |
8eaa0f34 ZD |
1074 | return false; |
1075 | } | |
1076 | else if (operand_equal_for_phi_arg_p (arg_false, smaller)) | |
1077 | { | |
1078 | /* Case | |
1079 | ||
1080 | if (smaller < larger) | |
1081 | { | |
1082 | r' = MIN_EXPR (larger, bound) | |
1083 | } | |
1084 | r = PHI <r', smaller> --> to be turned to MAX_EXPR. */ | |
1085 | if (ass_code != MIN_EXPR) | |
1086 | return false; | |
1087 | ||
1088 | minmax = MAX_EXPR; | |
1089 | if (operand_equal_for_phi_arg_p (op0, larger)) | |
1090 | bound = op1; | |
1091 | else if (operand_equal_for_phi_arg_p (op1, larger)) | |
1092 | bound = op0; | |
1093 | else | |
1094 | return false; | |
1095 | ||
1096 | /* We need BOUND >= SMALLER. */ | |
987b67bc KH |
1097 | if (!integer_nonzerop (fold_build2 (GE_EXPR, boolean_type_node, |
1098 | bound, smaller))) | |
8eaa0f34 ZD |
1099 | return false; |
1100 | } | |
1101 | else | |
1102 | return false; | |
1103 | } | |
1104 | else | |
1105 | { | |
1106 | /* We got here if the condition is false, i.e., SMALLER > LARGER. */ | |
1107 | if (!operand_equal_for_phi_arg_p (lhs, arg_false)) | |
1108 | return false; | |
1109 | ||
1110 | if (operand_equal_for_phi_arg_p (arg_true, larger)) | |
1111 | { | |
1112 | /* Case | |
1113 | ||
1114 | if (smaller > larger) | |
1115 | { | |
1116 | r' = MIN_EXPR (smaller, bound) | |
1117 | } | |
1118 | r = PHI <r', larger> --> to be turned to MAX_EXPR. */ | |
1119 | if (ass_code != MIN_EXPR) | |
1120 | return false; | |
1121 | ||
1122 | minmax = MAX_EXPR; | |
1123 | if (operand_equal_for_phi_arg_p (op0, smaller)) | |
1124 | bound = op1; | |
1125 | else if (operand_equal_for_phi_arg_p (op1, smaller)) | |
1126 | bound = op0; | |
1127 | else | |
1128 | return false; | |
1129 | ||
1130 | /* We need BOUND >= LARGER. */ | |
987b67bc KH |
1131 | if (!integer_nonzerop (fold_build2 (GE_EXPR, boolean_type_node, |
1132 | bound, larger))) | |
8eaa0f34 ZD |
1133 | return false; |
1134 | } | |
1135 | else if (operand_equal_for_phi_arg_p (arg_true, smaller)) | |
1136 | { | |
1137 | /* Case | |
1138 | ||
1139 | if (smaller > larger) | |
1140 | { | |
1141 | r' = MAX_EXPR (larger, bound) | |
1142 | } | |
1143 | r = PHI <r', smaller> --> to be turned to MIN_EXPR. */ | |
1144 | if (ass_code != MAX_EXPR) | |
1145 | return false; | |
1146 | ||
1147 | minmax = MIN_EXPR; | |
1148 | if (operand_equal_for_phi_arg_p (op0, larger)) | |
1149 | bound = op1; | |
1150 | else if (operand_equal_for_phi_arg_p (op1, larger)) | |
1151 | bound = op0; | |
1152 | else | |
1153 | return false; | |
1154 | ||
1155 | /* We need BOUND <= SMALLER. */ | |
987b67bc KH |
1156 | if (!integer_nonzerop (fold_build2 (LE_EXPR, boolean_type_node, |
1157 | bound, smaller))) | |
8eaa0f34 ZD |
1158 | return false; |
1159 | } | |
1160 | else | |
1161 | return false; | |
1162 | } | |
1163 | ||
1164 | /* Move the statement from the middle block. */ | |
726a989a | 1165 | gsi = gsi_last_bb (cond_bb); |
21719cea | 1166 | gsi_from = gsi_last_nondebug_bb (middle_bb); |
726a989a | 1167 | gsi_move_before (&gsi_from, &gsi); |
8eaa0f34 ZD |
1168 | } |
1169 | ||
1170 | /* Emit the statement to compute min/max. */ | |
1171 | result = duplicate_ssa_name (PHI_RESULT (phi), NULL); | |
0d0e4a03 | 1172 | new_stmt = gimple_build_assign (result, minmax, arg0, arg1); |
726a989a RB |
1173 | gsi = gsi_last_bb (cond_bb); |
1174 | gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT); | |
8eaa0f34 | 1175 | |
e5206274 | 1176 | replace_phi_edge_with_variable (cond_bb, e1, phi, result); |
8eaa0f34 ZD |
1177 | return true; |
1178 | } | |
1179 | ||
cc52902d AP |
1180 | /* The function absolute_replacement does the main work of doing the absolute |
1181 | replacement. Return true if the replacement is done. Otherwise return | |
1182 | false. | |
1183 | bb is the basic block where the replacement is going to be done on. arg0 | |
6c6cfbfd | 1184 | is argument 0 from the phi. Likewise for arg1. */ |
80c4ed35 | 1185 | |
cc52902d | 1186 | static bool |
80c4ed35 | 1187 | abs_replacement (basic_block cond_bb, basic_block middle_bb, |
e5206274 | 1188 | edge e0 ATTRIBUTE_UNUSED, edge e1, |
726a989a | 1189 | gimple phi, tree arg0, tree arg1) |
cc52902d AP |
1190 | { |
1191 | tree result; | |
538dd0b7 DM |
1192 | gassign *new_stmt; |
1193 | gimple cond; | |
726a989a | 1194 | gimple_stmt_iterator gsi; |
cc52902d | 1195 | edge true_edge, false_edge; |
726a989a | 1196 | gimple assign; |
cc52902d | 1197 | edge e; |
8eaa0f34 | 1198 | tree rhs, lhs; |
cc52902d AP |
1199 | bool negate; |
1200 | enum tree_code cond_code; | |
1201 | ||
1202 | /* If the type says honor signed zeros we cannot do this | |
471854f8 | 1203 | optimization. */ |
3d3dbadd | 1204 | if (HONOR_SIGNED_ZEROS (arg1)) |
cc52902d AP |
1205 | return false; |
1206 | ||
cc52902d AP |
1207 | /* OTHER_BLOCK must have only one executable statement which must have the |
1208 | form arg0 = -arg1 or arg1 = -arg0. */ | |
cc52902d | 1209 | |
8eaa0f34 | 1210 | assign = last_and_only_stmt (middle_bb); |
cc52902d AP |
1211 | /* If we did not find the proper negation assignment, then we can not |
1212 | optimize. */ | |
1213 | if (assign == NULL) | |
1214 | return false; | |
b8698a0f | 1215 | |
8eaa0f34 ZD |
1216 | /* If we got here, then we have found the only executable statement |
1217 | in OTHER_BLOCK. If it is anything other than arg = -arg1 or | |
1218 | arg1 = -arg0, then we can not optimize. */ | |
726a989a | 1219 | if (gimple_code (assign) != GIMPLE_ASSIGN) |
8eaa0f34 ZD |
1220 | return false; |
1221 | ||
726a989a | 1222 | lhs = gimple_assign_lhs (assign); |
8eaa0f34 | 1223 | |
726a989a | 1224 | if (gimple_assign_rhs_code (assign) != NEGATE_EXPR) |
8eaa0f34 ZD |
1225 | return false; |
1226 | ||
726a989a | 1227 | rhs = gimple_assign_rhs1 (assign); |
b8698a0f | 1228 | |
8eaa0f34 ZD |
1229 | /* The assignment has to be arg0 = -arg1 or arg1 = -arg0. */ |
1230 | if (!(lhs == arg0 && rhs == arg1) | |
1231 | && !(lhs == arg1 && rhs == arg0)) | |
1232 | return false; | |
cc52902d | 1233 | |
726a989a | 1234 | cond = last_stmt (cond_bb); |
cc52902d AP |
1235 | result = PHI_RESULT (phi); |
1236 | ||
1237 | /* Only relationals comparing arg[01] against zero are interesting. */ | |
726a989a | 1238 | cond_code = gimple_cond_code (cond); |
cc52902d AP |
1239 | if (cond_code != GT_EXPR && cond_code != GE_EXPR |
1240 | && cond_code != LT_EXPR && cond_code != LE_EXPR) | |
1241 | return false; | |
1242 | ||
471854f8 | 1243 | /* Make sure the conditional is arg[01] OP y. */ |
726a989a | 1244 | if (gimple_cond_lhs (cond) != rhs) |
cc52902d AP |
1245 | return false; |
1246 | ||
726a989a RB |
1247 | if (FLOAT_TYPE_P (TREE_TYPE (gimple_cond_rhs (cond))) |
1248 | ? real_zerop (gimple_cond_rhs (cond)) | |
1249 | : integer_zerop (gimple_cond_rhs (cond))) | |
cc52902d AP |
1250 | ; |
1251 | else | |
1252 | return false; | |
1253 | ||
1254 | /* We need to know which is the true edge and which is the false | |
1255 | edge so that we know if have abs or negative abs. */ | |
80c4ed35 | 1256 | extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge); |
cc52902d AP |
1257 | |
1258 | /* For GT_EXPR/GE_EXPR, if the true edge goes to OTHER_BLOCK, then we | |
1259 | will need to negate the result. Similarly for LT_EXPR/LE_EXPR if | |
1260 | the false edge goes to OTHER_BLOCK. */ | |
1261 | if (cond_code == GT_EXPR || cond_code == GE_EXPR) | |
1262 | e = true_edge; | |
1263 | else | |
1264 | e = false_edge; | |
0385f644 | 1265 | |
80c4ed35 | 1266 | if (e->dest == middle_bb) |
cc52902d AP |
1267 | negate = true; |
1268 | else | |
1269 | negate = false; | |
0385f644 | 1270 | |
80c4ed35 | 1271 | result = duplicate_ssa_name (result, NULL); |
0385f644 | 1272 | |
cc52902d | 1273 | if (negate) |
b731b390 | 1274 | lhs = make_ssa_name (TREE_TYPE (result)); |
cc52902d AP |
1275 | else |
1276 | lhs = result; | |
1277 | ||
471854f8 | 1278 | /* Build the modify expression with abs expression. */ |
0d0e4a03 | 1279 | new_stmt = gimple_build_assign (lhs, ABS_EXPR, rhs); |
cc52902d | 1280 | |
726a989a RB |
1281 | gsi = gsi_last_bb (cond_bb); |
1282 | gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT); | |
cc52902d AP |
1283 | |
1284 | if (negate) | |
1285 | { | |
726a989a | 1286 | /* Get the right GSI. We want to insert after the recently |
cc52902d AP |
1287 | added ABS_EXPR statement (which we know is the first statement |
1288 | in the block. */ | |
0d0e4a03 | 1289 | new_stmt = gimple_build_assign (result, NEGATE_EXPR, lhs); |
cc52902d | 1290 | |
726a989a | 1291 | gsi_insert_after (&gsi, new_stmt, GSI_NEW_STMT); |
cc52902d | 1292 | } |
0385f644 | 1293 | |
e5206274 | 1294 | replace_phi_edge_with_variable (cond_bb, e1, phi, result); |
cc52902d AP |
1295 | |
1296 | /* Note that we optimized this PHI. */ | |
1297 | return true; | |
1298 | } | |
1299 | ||
a5828d1e MM |
1300 | /* Auxiliary functions to determine the set of memory accesses which |
1301 | can't trap because they are preceded by accesses to the same memory | |
70f34814 | 1302 | portion. We do that for MEM_REFs, so we only need to track |
a5828d1e MM |
1303 | the SSA_NAME of the pointer indirectly referenced. The algorithm |
1304 | simply is a walk over all instructions in dominator order. When | |
70f34814 | 1305 | we see an MEM_REF we determine if we've already seen a same |
a5828d1e | 1306 | ref anywhere up to the root of the dominator tree. If we do the |
e08f02f0 | 1307 | current access can't trap. If we don't see any dominating access |
a5828d1e | 1308 | the current access might trap, but might also make later accesses |
e08f02f0 MM |
1309 | non-trapping, so we remember it. We need to be careful with loads |
1310 | or stores, for instance a load might not trap, while a store would, | |
1311 | so if we see a dominating read access this doesn't mean that a later | |
1312 | write access would not trap. Hence we also need to differentiate the | |
1313 | type of access(es) seen. | |
1314 | ||
1315 | ??? We currently are very conservative and assume that a load might | |
1316 | trap even if a store doesn't (write-only memory). This probably is | |
1317 | overly conservative. */ | |
a5828d1e | 1318 | |
70f34814 | 1319 | /* A hash-table of SSA_NAMEs, and in which basic block an MEM_REF |
a5828d1e MM |
1320 | through it was seen, which would constitute a no-trap region for |
1321 | same accesses. */ | |
1322 | struct name_to_bb | |
1323 | { | |
69ef9a79 | 1324 | unsigned int ssa_name_ver; |
c1ca73d8 | 1325 | unsigned int phase; |
69ef9a79 JJ |
1326 | bool store; |
1327 | HOST_WIDE_INT offset, size; | |
a5828d1e MM |
1328 | basic_block bb; |
1329 | }; | |
1330 | ||
4a8fb1a1 LC |
1331 | /* Hashtable helpers. */ |
1332 | ||
1333 | struct ssa_names_hasher : typed_free_remove <name_to_bb> | |
1334 | { | |
67f58944 TS |
1335 | typedef name_to_bb *value_type; |
1336 | typedef name_to_bb *compare_type; | |
1337 | static inline hashval_t hash (const name_to_bb *); | |
1338 | static inline bool equal (const name_to_bb *, const name_to_bb *); | |
4a8fb1a1 | 1339 | }; |
a5828d1e | 1340 | |
c1ca73d8 MM |
1341 | /* Used for quick clearing of the hash-table when we see calls. |
1342 | Hash entries with phase < nt_call_phase are invalid. */ | |
1343 | static unsigned int nt_call_phase; | |
1344 | ||
69ef9a79 | 1345 | /* The hash function. */ |
4a8fb1a1 LC |
1346 | |
1347 | inline hashval_t | |
67f58944 | 1348 | ssa_names_hasher::hash (const name_to_bb *n) |
a5828d1e | 1349 | { |
69ef9a79 JJ |
1350 | return n->ssa_name_ver ^ (((hashval_t) n->store) << 31) |
1351 | ^ (n->offset << 6) ^ (n->size << 3); | |
a5828d1e MM |
1352 | } |
1353 | ||
69ef9a79 | 1354 | /* The equality function of *P1 and *P2. */ |
a5828d1e | 1355 | |
4a8fb1a1 | 1356 | inline bool |
67f58944 | 1357 | ssa_names_hasher::equal (const name_to_bb *n1, const name_to_bb *n2) |
4a8fb1a1 | 1358 | { |
69ef9a79 JJ |
1359 | return n1->ssa_name_ver == n2->ssa_name_ver |
1360 | && n1->store == n2->store | |
1361 | && n1->offset == n2->offset | |
1362 | && n1->size == n2->size; | |
a5828d1e MM |
1363 | } |
1364 | ||
c203e8a7 TS |
1365 | class nontrapping_dom_walker : public dom_walker |
1366 | { | |
1367 | public: | |
6e2830c3 | 1368 | nontrapping_dom_walker (cdi_direction direction, hash_set<tree> *ps) |
c203e8a7 TS |
1369 | : dom_walker (direction), m_nontrapping (ps), m_seen_ssa_names (128) {} |
1370 | ||
1371 | virtual void before_dom_children (basic_block); | |
1372 | virtual void after_dom_children (basic_block); | |
1373 | ||
1374 | private: | |
1375 | ||
1376 | /* We see the expression EXP in basic block BB. If it's an interesting | |
1377 | expression (an MEM_REF through an SSA_NAME) possibly insert the | |
1378 | expression into the set NONTRAP or the hash table of seen expressions. | |
1379 | STORE is true if this expression is on the LHS, otherwise it's on | |
1380 | the RHS. */ | |
1381 | void add_or_mark_expr (basic_block, tree, bool); | |
1382 | ||
6e2830c3 | 1383 | hash_set<tree> *m_nontrapping; |
c203e8a7 TS |
1384 | |
1385 | /* The hash table for remembering what we've seen. */ | |
1386 | hash_table<ssa_names_hasher> m_seen_ssa_names; | |
1387 | }; | |
1388 | ||
1389 | /* Called by walk_dominator_tree, when entering the block BB. */ | |
1390 | void | |
1391 | nontrapping_dom_walker::before_dom_children (basic_block bb) | |
1392 | { | |
1393 | edge e; | |
1394 | edge_iterator ei; | |
1395 | gimple_stmt_iterator gsi; | |
1396 | ||
1397 | /* If we haven't seen all our predecessors, clear the hash-table. */ | |
1398 | FOR_EACH_EDGE (e, ei, bb->preds) | |
1399 | if ((((size_t)e->src->aux) & 2) == 0) | |
1400 | { | |
1401 | nt_call_phase++; | |
1402 | break; | |
1403 | } | |
1404 | ||
1405 | /* Mark this BB as being on the path to dominator root and as visited. */ | |
1406 | bb->aux = (void*)(1 | 2); | |
1407 | ||
1408 | /* And walk the statements in order. */ | |
1409 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
1410 | { | |
1411 | gimple stmt = gsi_stmt (gsi); | |
1412 | ||
1413 | if (is_gimple_call (stmt) && !nonfreeing_call_p (stmt)) | |
1414 | nt_call_phase++; | |
1415 | else if (gimple_assign_single_p (stmt) && !gimple_has_volatile_ops (stmt)) | |
1416 | { | |
1417 | add_or_mark_expr (bb, gimple_assign_lhs (stmt), true); | |
1418 | add_or_mark_expr (bb, gimple_assign_rhs1 (stmt), false); | |
1419 | } | |
1420 | } | |
1421 | } | |
1422 | ||
1423 | /* Called by walk_dominator_tree, when basic block BB is exited. */ | |
1424 | void | |
1425 | nontrapping_dom_walker::after_dom_children (basic_block bb) | |
1426 | { | |
1427 | /* This BB isn't on the path to dominator root anymore. */ | |
1428 | bb->aux = (void*)2; | |
1429 | } | |
4a8fb1a1 | 1430 | |
fa10beec | 1431 | /* We see the expression EXP in basic block BB. If it's an interesting |
70f34814 | 1432 | expression (an MEM_REF through an SSA_NAME) possibly insert the |
e08f02f0 MM |
1433 | expression into the set NONTRAP or the hash table of seen expressions. |
1434 | STORE is true if this expression is on the LHS, otherwise it's on | |
1435 | the RHS. */ | |
c203e8a7 TS |
1436 | void |
1437 | nontrapping_dom_walker::add_or_mark_expr (basic_block bb, tree exp, bool store) | |
a5828d1e | 1438 | { |
69ef9a79 JJ |
1439 | HOST_WIDE_INT size; |
1440 | ||
70f34814 | 1441 | if (TREE_CODE (exp) == MEM_REF |
69ef9a79 | 1442 | && TREE_CODE (TREE_OPERAND (exp, 0)) == SSA_NAME |
9541ffee | 1443 | && tree_fits_shwi_p (TREE_OPERAND (exp, 1)) |
69ef9a79 | 1444 | && (size = int_size_in_bytes (TREE_TYPE (exp))) > 0) |
a5828d1e MM |
1445 | { |
1446 | tree name = TREE_OPERAND (exp, 0); | |
1447 | struct name_to_bb map; | |
4a8fb1a1 | 1448 | name_to_bb **slot; |
e08f02f0 | 1449 | struct name_to_bb *n2bb; |
a5828d1e MM |
1450 | basic_block found_bb = 0; |
1451 | ||
70f34814 | 1452 | /* Try to find the last seen MEM_REF through the same |
a5828d1e | 1453 | SSA_NAME, which can trap. */ |
69ef9a79 | 1454 | map.ssa_name_ver = SSA_NAME_VERSION (name); |
c1ca73d8 | 1455 | map.phase = 0; |
a5828d1e | 1456 | map.bb = 0; |
e08f02f0 | 1457 | map.store = store; |
9439e9a1 | 1458 | map.offset = tree_to_shwi (TREE_OPERAND (exp, 1)); |
69ef9a79 JJ |
1459 | map.size = size; |
1460 | ||
c203e8a7 | 1461 | slot = m_seen_ssa_names.find_slot (&map, INSERT); |
4a8fb1a1 | 1462 | n2bb = *slot; |
c1ca73d8 | 1463 | if (n2bb && n2bb->phase >= nt_call_phase) |
e08f02f0 | 1464 | found_bb = n2bb->bb; |
a5828d1e | 1465 | |
70f34814 | 1466 | /* If we've found a trapping MEM_REF, _and_ it dominates EXP |
a5828d1e MM |
1467 | (it's in a basic block on the path from us to the dominator root) |
1468 | then we can't trap. */ | |
c1ca73d8 | 1469 | if (found_bb && (((size_t)found_bb->aux) & 1) == 1) |
a5828d1e | 1470 | { |
6e2830c3 | 1471 | m_nontrapping->add (exp); |
a5828d1e MM |
1472 | } |
1473 | else | |
1474 | { | |
1475 | /* EXP might trap, so insert it into the hash table. */ | |
e08f02f0 | 1476 | if (n2bb) |
a5828d1e | 1477 | { |
c1ca73d8 | 1478 | n2bb->phase = nt_call_phase; |
e08f02f0 | 1479 | n2bb->bb = bb; |
a5828d1e MM |
1480 | } |
1481 | else | |
1482 | { | |
e08f02f0 | 1483 | n2bb = XNEW (struct name_to_bb); |
69ef9a79 | 1484 | n2bb->ssa_name_ver = SSA_NAME_VERSION (name); |
c1ca73d8 | 1485 | n2bb->phase = nt_call_phase; |
e08f02f0 MM |
1486 | n2bb->bb = bb; |
1487 | n2bb->store = store; | |
69ef9a79 JJ |
1488 | n2bb->offset = map.offset; |
1489 | n2bb->size = size; | |
e08f02f0 | 1490 | *slot = n2bb; |
a5828d1e MM |
1491 | } |
1492 | } | |
1493 | } | |
1494 | } | |
1495 | ||
a5828d1e MM |
1496 | /* This is the entry point of gathering non trapping memory accesses. |
1497 | It will do a dominator walk over the whole function, and it will | |
1498 | make use of the bb->aux pointers. It returns a set of trees | |
70f34814 | 1499 | (the MEM_REFs itself) which can't trap. */ |
6e2830c3 | 1500 | static hash_set<tree> * |
a5828d1e MM |
1501 | get_non_trapping (void) |
1502 | { | |
c1ca73d8 | 1503 | nt_call_phase = 0; |
6e2830c3 | 1504 | hash_set<tree> *nontrap = new hash_set<tree>; |
a5828d1e MM |
1505 | /* We're going to do a dominator walk, so ensure that we have |
1506 | dominance information. */ | |
1507 | calculate_dominance_info (CDI_DOMINATORS); | |
1508 | ||
4d9192b5 TS |
1509 | nontrapping_dom_walker (CDI_DOMINATORS, nontrap) |
1510 | .walk (cfun->cfg->x_entry_block_ptr); | |
1511 | ||
c1ca73d8 | 1512 | clear_aux_for_blocks (); |
a5828d1e MM |
1513 | return nontrap; |
1514 | } | |
1515 | ||
1516 | /* Do the main work of conditional store replacement. We already know | |
1517 | that the recognized pattern looks like so: | |
1518 | ||
1519 | split: | |
1520 | if (cond) goto MIDDLE_BB; else goto JOIN_BB (edge E1) | |
1521 | MIDDLE_BB: | |
1522 | something | |
1523 | fallthrough (edge E0) | |
1524 | JOIN_BB: | |
1525 | some more | |
1526 | ||
1527 | We check that MIDDLE_BB contains only one store, that that store | |
1528 | doesn't trap (not via NOTRAP, but via checking if an access to the same | |
1529 | memory location dominates us) and that the store has a "simple" RHS. */ | |
1530 | ||
1531 | static bool | |
1532 | cond_store_replacement (basic_block middle_bb, basic_block join_bb, | |
6e2830c3 | 1533 | edge e0, edge e1, hash_set<tree> *nontrap) |
a5828d1e | 1534 | { |
726a989a | 1535 | gimple assign = last_and_only_stmt (middle_bb); |
83d5977e | 1536 | tree lhs, rhs, name, name2; |
538dd0b7 DM |
1537 | gphi *newphi; |
1538 | gassign *new_stmt; | |
726a989a | 1539 | gimple_stmt_iterator gsi; |
f5045c96 | 1540 | source_location locus; |
a5828d1e MM |
1541 | |
1542 | /* Check if middle_bb contains of only one store. */ | |
1543 | if (!assign | |
d7fa6ee2 JJ |
1544 | || !gimple_assign_single_p (assign) |
1545 | || gimple_has_volatile_ops (assign)) | |
a5828d1e MM |
1546 | return false; |
1547 | ||
f5045c96 | 1548 | locus = gimple_location (assign); |
726a989a RB |
1549 | lhs = gimple_assign_lhs (assign); |
1550 | rhs = gimple_assign_rhs1 (assign); | |
70f34814 | 1551 | if (TREE_CODE (lhs) != MEM_REF |
23782cc3 | 1552 | || TREE_CODE (TREE_OPERAND (lhs, 0)) != SSA_NAME |
742d143c | 1553 | || !is_gimple_reg_type (TREE_TYPE (lhs))) |
a5828d1e | 1554 | return false; |
23782cc3 | 1555 | |
a5828d1e MM |
1556 | /* Prove that we can move the store down. We could also check |
1557 | TREE_THIS_NOTRAP here, but in that case we also could move stores, | |
1558 | whose value is not available readily, which we want to avoid. */ | |
6e2830c3 | 1559 | if (!nontrap->contains (lhs)) |
a5828d1e MM |
1560 | return false; |
1561 | ||
1562 | /* Now we've checked the constraints, so do the transformation: | |
1563 | 1) Remove the single store. */ | |
726a989a | 1564 | gsi = gsi_for_stmt (assign); |
742d143c | 1565 | unlink_stmt_vdef (assign); |
726a989a | 1566 | gsi_remove (&gsi, true); |
23782cc3 | 1567 | release_defs (assign); |
a5828d1e | 1568 | |
83d5977e | 1569 | /* 2) Insert a load from the memory of the store to the temporary |
a5828d1e MM |
1570 | on the edge which did not contain the store. */ |
1571 | lhs = unshare_expr (lhs); | |
83d5977e RG |
1572 | name = make_temp_ssa_name (TREE_TYPE (lhs), NULL, "cstore"); |
1573 | new_stmt = gimple_build_assign (name, lhs); | |
f5045c96 | 1574 | gimple_set_location (new_stmt, locus); |
726a989a | 1575 | gsi_insert_on_edge (e1, new_stmt); |
a5828d1e | 1576 | |
83d5977e | 1577 | /* 3) Create a PHI node at the join block, with one argument |
a5828d1e MM |
1578 | holding the old RHS, and the other holding the temporary |
1579 | where we stored the old memory contents. */ | |
83d5977e RG |
1580 | name2 = make_temp_ssa_name (TREE_TYPE (lhs), NULL, "cstore"); |
1581 | newphi = create_phi_node (name2, join_bb); | |
9e227d60 DC |
1582 | add_phi_arg (newphi, rhs, e0, locus); |
1583 | add_phi_arg (newphi, name, e1, locus); | |
a5828d1e MM |
1584 | |
1585 | lhs = unshare_expr (lhs); | |
726a989a | 1586 | new_stmt = gimple_build_assign (lhs, PHI_RESULT (newphi)); |
a5828d1e | 1587 | |
83d5977e | 1588 | /* 4) Insert that PHI node. */ |
726a989a RB |
1589 | gsi = gsi_after_labels (join_bb); |
1590 | if (gsi_end_p (gsi)) | |
a5828d1e | 1591 | { |
726a989a RB |
1592 | gsi = gsi_last_bb (join_bb); |
1593 | gsi_insert_after (&gsi, new_stmt, GSI_NEW_STMT); | |
a5828d1e MM |
1594 | } |
1595 | else | |
726a989a | 1596 | gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT); |
a5828d1e MM |
1597 | |
1598 | return true; | |
1599 | } | |
6de9cd9a | 1600 | |
bfe068c3 | 1601 | /* Do the main work of conditional store replacement. */ |
23782cc3 JJ |
1602 | |
1603 | static bool | |
bfe068c3 IR |
1604 | cond_if_else_store_replacement_1 (basic_block then_bb, basic_block else_bb, |
1605 | basic_block join_bb, gimple then_assign, | |
1606 | gimple else_assign) | |
23782cc3 | 1607 | { |
83d5977e | 1608 | tree lhs_base, lhs, then_rhs, else_rhs, name; |
23782cc3 JJ |
1609 | source_location then_locus, else_locus; |
1610 | gimple_stmt_iterator gsi; | |
538dd0b7 DM |
1611 | gphi *newphi; |
1612 | gassign *new_stmt; | |
23782cc3 | 1613 | |
23782cc3 JJ |
1614 | if (then_assign == NULL |
1615 | || !gimple_assign_single_p (then_assign) | |
47598145 | 1616 | || gimple_clobber_p (then_assign) |
d7fa6ee2 | 1617 | || gimple_has_volatile_ops (then_assign) |
23782cc3 | 1618 | || else_assign == NULL |
47598145 | 1619 | || !gimple_assign_single_p (else_assign) |
d7fa6ee2 JJ |
1620 | || gimple_clobber_p (else_assign) |
1621 | || gimple_has_volatile_ops (else_assign)) | |
23782cc3 JJ |
1622 | return false; |
1623 | ||
1624 | lhs = gimple_assign_lhs (then_assign); | |
1625 | if (!is_gimple_reg_type (TREE_TYPE (lhs)) | |
1626 | || !operand_equal_p (lhs, gimple_assign_lhs (else_assign), 0)) | |
1627 | return false; | |
1628 | ||
1629 | lhs_base = get_base_address (lhs); | |
1630 | if (lhs_base == NULL_TREE | |
1631 | || (!DECL_P (lhs_base) && TREE_CODE (lhs_base) != MEM_REF)) | |
1632 | return false; | |
1633 | ||
1634 | then_rhs = gimple_assign_rhs1 (then_assign); | |
1635 | else_rhs = gimple_assign_rhs1 (else_assign); | |
1636 | then_locus = gimple_location (then_assign); | |
1637 | else_locus = gimple_location (else_assign); | |
1638 | ||
1639 | /* Now we've checked the constraints, so do the transformation: | |
1640 | 1) Remove the stores. */ | |
1641 | gsi = gsi_for_stmt (then_assign); | |
1642 | unlink_stmt_vdef (then_assign); | |
1643 | gsi_remove (&gsi, true); | |
1644 | release_defs (then_assign); | |
1645 | ||
1646 | gsi = gsi_for_stmt (else_assign); | |
1647 | unlink_stmt_vdef (else_assign); | |
1648 | gsi_remove (&gsi, true); | |
1649 | release_defs (else_assign); | |
1650 | ||
83d5977e | 1651 | /* 2) Create a PHI node at the join block, with one argument |
23782cc3 JJ |
1652 | holding the old RHS, and the other holding the temporary |
1653 | where we stored the old memory contents. */ | |
83d5977e RG |
1654 | name = make_temp_ssa_name (TREE_TYPE (lhs), NULL, "cstore"); |
1655 | newphi = create_phi_node (name, join_bb); | |
9e227d60 DC |
1656 | add_phi_arg (newphi, then_rhs, EDGE_SUCC (then_bb, 0), then_locus); |
1657 | add_phi_arg (newphi, else_rhs, EDGE_SUCC (else_bb, 0), else_locus); | |
23782cc3 JJ |
1658 | |
1659 | new_stmt = gimple_build_assign (lhs, PHI_RESULT (newphi)); | |
1660 | ||
83d5977e | 1661 | /* 3) Insert that PHI node. */ |
23782cc3 JJ |
1662 | gsi = gsi_after_labels (join_bb); |
1663 | if (gsi_end_p (gsi)) | |
1664 | { | |
1665 | gsi = gsi_last_bb (join_bb); | |
1666 | gsi_insert_after (&gsi, new_stmt, GSI_NEW_STMT); | |
1667 | } | |
1668 | else | |
1669 | gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT); | |
1670 | ||
1671 | return true; | |
1672 | } | |
1673 | ||
bfe068c3 IR |
1674 | /* Conditional store replacement. We already know |
1675 | that the recognized pattern looks like so: | |
1676 | ||
1677 | split: | |
1678 | if (cond) goto THEN_BB; else goto ELSE_BB (edge E1) | |
1679 | THEN_BB: | |
1680 | ... | |
1681 | X = Y; | |
1682 | ... | |
1683 | goto JOIN_BB; | |
1684 | ELSE_BB: | |
1685 | ... | |
1686 | X = Z; | |
1687 | ... | |
1688 | fallthrough (edge E0) | |
1689 | JOIN_BB: | |
1690 | some more | |
1691 | ||
1692 | We check that it is safe to sink the store to JOIN_BB by verifying that | |
1693 | there are no read-after-write or write-after-write dependencies in | |
1694 | THEN_BB and ELSE_BB. */ | |
1695 | ||
1696 | static bool | |
1697 | cond_if_else_store_replacement (basic_block then_bb, basic_block else_bb, | |
1698 | basic_block join_bb) | |
1699 | { | |
1700 | gimple then_assign = last_and_only_stmt (then_bb); | |
1701 | gimple else_assign = last_and_only_stmt (else_bb); | |
9771b263 DN |
1702 | vec<data_reference_p> then_datarefs, else_datarefs; |
1703 | vec<ddr_p> then_ddrs, else_ddrs; | |
bfe068c3 IR |
1704 | gimple then_store, else_store; |
1705 | bool found, ok = false, res; | |
1706 | struct data_dependence_relation *ddr; | |
1707 | data_reference_p then_dr, else_dr; | |
1708 | int i, j; | |
1709 | tree then_lhs, else_lhs; | |
bfe068c3 IR |
1710 | basic_block blocks[3]; |
1711 | ||
1712 | if (MAX_STORES_TO_SINK == 0) | |
1713 | return false; | |
1714 | ||
1715 | /* Handle the case with single statement in THEN_BB and ELSE_BB. */ | |
1716 | if (then_assign && else_assign) | |
1717 | return cond_if_else_store_replacement_1 (then_bb, else_bb, join_bb, | |
1718 | then_assign, else_assign); | |
1719 | ||
1720 | /* Find data references. */ | |
9771b263 DN |
1721 | then_datarefs.create (1); |
1722 | else_datarefs.create (1); | |
bfe068c3 IR |
1723 | if ((find_data_references_in_bb (NULL, then_bb, &then_datarefs) |
1724 | == chrec_dont_know) | |
9771b263 | 1725 | || !then_datarefs.length () |
bfe068c3 | 1726 | || (find_data_references_in_bb (NULL, else_bb, &else_datarefs) |
5ce9450f | 1727 | == chrec_dont_know) |
9771b263 | 1728 | || !else_datarefs.length ()) |
bfe068c3 IR |
1729 | { |
1730 | free_data_refs (then_datarefs); | |
1731 | free_data_refs (else_datarefs); | |
1732 | return false; | |
1733 | } | |
1734 | ||
1735 | /* Find pairs of stores with equal LHS. */ | |
00f96dc9 | 1736 | auto_vec<gimple, 1> then_stores, else_stores; |
9771b263 | 1737 | FOR_EACH_VEC_ELT (then_datarefs, i, then_dr) |
bfe068c3 IR |
1738 | { |
1739 | if (DR_IS_READ (then_dr)) | |
1740 | continue; | |
1741 | ||
1742 | then_store = DR_STMT (then_dr); | |
59daeef4 | 1743 | then_lhs = gimple_get_lhs (then_store); |
5ce9450f JJ |
1744 | if (then_lhs == NULL_TREE) |
1745 | continue; | |
bfe068c3 IR |
1746 | found = false; |
1747 | ||
9771b263 | 1748 | FOR_EACH_VEC_ELT (else_datarefs, j, else_dr) |
bfe068c3 IR |
1749 | { |
1750 | if (DR_IS_READ (else_dr)) | |
1751 | continue; | |
1752 | ||
1753 | else_store = DR_STMT (else_dr); | |
59daeef4 | 1754 | else_lhs = gimple_get_lhs (else_store); |
5ce9450f JJ |
1755 | if (else_lhs == NULL_TREE) |
1756 | continue; | |
bfe068c3 IR |
1757 | |
1758 | if (operand_equal_p (then_lhs, else_lhs, 0)) | |
1759 | { | |
1760 | found = true; | |
1761 | break; | |
1762 | } | |
1763 | } | |
1764 | ||
1765 | if (!found) | |
1766 | continue; | |
1767 | ||
9771b263 DN |
1768 | then_stores.safe_push (then_store); |
1769 | else_stores.safe_push (else_store); | |
bfe068c3 IR |
1770 | } |
1771 | ||
1772 | /* No pairs of stores found. */ | |
9771b263 DN |
1773 | if (!then_stores.length () |
1774 | || then_stores.length () > (unsigned) MAX_STORES_TO_SINK) | |
bfe068c3 IR |
1775 | { |
1776 | free_data_refs (then_datarefs); | |
1777 | free_data_refs (else_datarefs); | |
bfe068c3 IR |
1778 | return false; |
1779 | } | |
1780 | ||
1781 | /* Compute and check data dependencies in both basic blocks. */ | |
9771b263 DN |
1782 | then_ddrs.create (1); |
1783 | else_ddrs.create (1); | |
1784 | if (!compute_all_dependences (then_datarefs, &then_ddrs, | |
6e1aa848 | 1785 | vNULL, false) |
9771b263 | 1786 | || !compute_all_dependences (else_datarefs, &else_ddrs, |
6e1aa848 | 1787 | vNULL, false)) |
795e8869 JJ |
1788 | { |
1789 | free_dependence_relations (then_ddrs); | |
1790 | free_dependence_relations (else_ddrs); | |
1791 | free_data_refs (then_datarefs); | |
1792 | free_data_refs (else_datarefs); | |
795e8869 JJ |
1793 | return false; |
1794 | } | |
bfe068c3 IR |
1795 | blocks[0] = then_bb; |
1796 | blocks[1] = else_bb; | |
1797 | blocks[2] = join_bb; | |
1798 | renumber_gimple_stmt_uids_in_blocks (blocks, 3); | |
1799 | ||
1800 | /* Check that there are no read-after-write or write-after-write dependencies | |
1801 | in THEN_BB. */ | |
9771b263 | 1802 | FOR_EACH_VEC_ELT (then_ddrs, i, ddr) |
bfe068c3 IR |
1803 | { |
1804 | struct data_reference *dra = DDR_A (ddr); | |
1805 | struct data_reference *drb = DDR_B (ddr); | |
1806 | ||
1807 | if (DDR_ARE_DEPENDENT (ddr) != chrec_known | |
1808 | && ((DR_IS_READ (dra) && DR_IS_WRITE (drb) | |
1809 | && gimple_uid (DR_STMT (dra)) > gimple_uid (DR_STMT (drb))) | |
1810 | || (DR_IS_READ (drb) && DR_IS_WRITE (dra) | |
1811 | && gimple_uid (DR_STMT (drb)) > gimple_uid (DR_STMT (dra))) | |
1812 | || (DR_IS_WRITE (dra) && DR_IS_WRITE (drb)))) | |
1813 | { | |
1814 | free_dependence_relations (then_ddrs); | |
1815 | free_dependence_relations (else_ddrs); | |
dbaa912c RG |
1816 | free_data_refs (then_datarefs); |
1817 | free_data_refs (else_datarefs); | |
bfe068c3 IR |
1818 | return false; |
1819 | } | |
1820 | } | |
1821 | ||
1822 | /* Check that there are no read-after-write or write-after-write dependencies | |
1823 | in ELSE_BB. */ | |
9771b263 | 1824 | FOR_EACH_VEC_ELT (else_ddrs, i, ddr) |
bfe068c3 IR |
1825 | { |
1826 | struct data_reference *dra = DDR_A (ddr); | |
1827 | struct data_reference *drb = DDR_B (ddr); | |
1828 | ||
1829 | if (DDR_ARE_DEPENDENT (ddr) != chrec_known | |
1830 | && ((DR_IS_READ (dra) && DR_IS_WRITE (drb) | |
1831 | && gimple_uid (DR_STMT (dra)) > gimple_uid (DR_STMT (drb))) | |
1832 | || (DR_IS_READ (drb) && DR_IS_WRITE (dra) | |
1833 | && gimple_uid (DR_STMT (drb)) > gimple_uid (DR_STMT (dra))) | |
1834 | || (DR_IS_WRITE (dra) && DR_IS_WRITE (drb)))) | |
1835 | { | |
1836 | free_dependence_relations (then_ddrs); | |
1837 | free_dependence_relations (else_ddrs); | |
dbaa912c RG |
1838 | free_data_refs (then_datarefs); |
1839 | free_data_refs (else_datarefs); | |
bfe068c3 IR |
1840 | return false; |
1841 | } | |
1842 | } | |
1843 | ||
1844 | /* Sink stores with same LHS. */ | |
9771b263 | 1845 | FOR_EACH_VEC_ELT (then_stores, i, then_store) |
bfe068c3 | 1846 | { |
9771b263 | 1847 | else_store = else_stores[i]; |
bfe068c3 IR |
1848 | res = cond_if_else_store_replacement_1 (then_bb, else_bb, join_bb, |
1849 | then_store, else_store); | |
1850 | ok = ok || res; | |
1851 | } | |
1852 | ||
1853 | free_dependence_relations (then_ddrs); | |
1854 | free_dependence_relations (else_ddrs); | |
dbaa912c RG |
1855 | free_data_refs (then_datarefs); |
1856 | free_data_refs (else_datarefs); | |
bfe068c3 IR |
1857 | |
1858 | return ok; | |
1859 | } | |
1860 | ||
372a6eb8 BS |
1861 | /* Return TRUE if STMT has a VUSE whose corresponding VDEF is in BB. */ |
1862 | ||
1863 | static bool | |
1864 | local_mem_dependence (gimple stmt, basic_block bb) | |
1865 | { | |
1866 | tree vuse = gimple_vuse (stmt); | |
1867 | gimple def; | |
1868 | ||
1869 | if (!vuse) | |
1870 | return false; | |
1871 | ||
1872 | def = SSA_NAME_DEF_STMT (vuse); | |
1873 | return (def && gimple_bb (def) == bb); | |
1874 | } | |
1875 | ||
1876 | /* Given a "diamond" control-flow pattern where BB0 tests a condition, | |
1877 | BB1 and BB2 are "then" and "else" blocks dependent on this test, | |
c9ef86a1 | 1878 | and BB3 rejoins control flow following BB1 and BB2, look for |
372a6eb8 BS |
1879 | opportunities to hoist loads as follows. If BB3 contains a PHI of |
1880 | two loads, one each occurring in BB1 and BB2, and the loads are | |
1881 | provably of adjacent fields in the same structure, then move both | |
1882 | loads into BB0. Of course this can only be done if there are no | |
1883 | dependencies preventing such motion. | |
1884 | ||
1885 | One of the hoisted loads will always be speculative, so the | |
1886 | transformation is currently conservative: | |
1887 | ||
1888 | - The fields must be strictly adjacent. | |
1889 | - The two fields must occupy a single memory block that is | |
1890 | guaranteed to not cross a page boundary. | |
1891 | ||
1892 | The last is difficult to prove, as such memory blocks should be | |
1893 | aligned on the minimum of the stack alignment boundary and the | |
1894 | alignment guaranteed by heap allocation interfaces. Thus we rely | |
1895 | on a parameter for the alignment value. | |
1896 | ||
1897 | Provided a good value is used for the last case, the first | |
1898 | restriction could possibly be relaxed. */ | |
1899 | ||
1900 | static void | |
1901 | hoist_adjacent_loads (basic_block bb0, basic_block bb1, | |
1902 | basic_block bb2, basic_block bb3) | |
1903 | { | |
1904 | int param_align = PARAM_VALUE (PARAM_L1_CACHE_LINE_SIZE); | |
1905 | unsigned param_align_bits = (unsigned) (param_align * BITS_PER_UNIT); | |
538dd0b7 | 1906 | gphi_iterator gsi; |
372a6eb8 BS |
1907 | |
1908 | /* Walk the phis in bb3 looking for an opportunity. We are looking | |
1909 | for phis of two SSA names, one each of which is defined in bb1 and | |
1910 | bb2. */ | |
1911 | for (gsi = gsi_start_phis (bb3); !gsi_end_p (gsi); gsi_next (&gsi)) | |
1912 | { | |
538dd0b7 | 1913 | gphi *phi_stmt = gsi.phi (); |
372a6eb8 BS |
1914 | gimple def1, def2, defswap; |
1915 | tree arg1, arg2, ref1, ref2, field1, field2, fieldswap; | |
1916 | tree tree_offset1, tree_offset2, tree_size2, next; | |
1917 | int offset1, offset2, size2; | |
1918 | unsigned align1; | |
1919 | gimple_stmt_iterator gsi2; | |
1920 | basic_block bb_for_def1, bb_for_def2; | |
1921 | ||
ea057359 RG |
1922 | if (gimple_phi_num_args (phi_stmt) != 2 |
1923 | || virtual_operand_p (gimple_phi_result (phi_stmt))) | |
372a6eb8 BS |
1924 | continue; |
1925 | ||
1926 | arg1 = gimple_phi_arg_def (phi_stmt, 0); | |
1927 | arg2 = gimple_phi_arg_def (phi_stmt, 1); | |
c9ef86a1 | 1928 | |
372a6eb8 BS |
1929 | if (TREE_CODE (arg1) != SSA_NAME |
1930 | || TREE_CODE (arg2) != SSA_NAME | |
1931 | || SSA_NAME_IS_DEFAULT_DEF (arg1) | |
ea057359 | 1932 | || SSA_NAME_IS_DEFAULT_DEF (arg2)) |
372a6eb8 BS |
1933 | continue; |
1934 | ||
1935 | def1 = SSA_NAME_DEF_STMT (arg1); | |
1936 | def2 = SSA_NAME_DEF_STMT (arg2); | |
1937 | ||
1938 | if ((gimple_bb (def1) != bb1 || gimple_bb (def2) != bb2) | |
1939 | && (gimple_bb (def2) != bb1 || gimple_bb (def1) != bb2)) | |
1940 | continue; | |
1941 | ||
1942 | /* Check the mode of the arguments to be sure a conditional move | |
1943 | can be generated for it. */ | |
0a5f2683 BS |
1944 | if (optab_handler (movcc_optab, TYPE_MODE (TREE_TYPE (arg1))) |
1945 | == CODE_FOR_nothing) | |
372a6eb8 BS |
1946 | continue; |
1947 | ||
1948 | /* Both statements must be assignments whose RHS is a COMPONENT_REF. */ | |
1949 | if (!gimple_assign_single_p (def1) | |
d7fa6ee2 JJ |
1950 | || !gimple_assign_single_p (def2) |
1951 | || gimple_has_volatile_ops (def1) | |
1952 | || gimple_has_volatile_ops (def2)) | |
372a6eb8 BS |
1953 | continue; |
1954 | ||
1955 | ref1 = gimple_assign_rhs1 (def1); | |
1956 | ref2 = gimple_assign_rhs1 (def2); | |
1957 | ||
1958 | if (TREE_CODE (ref1) != COMPONENT_REF | |
1959 | || TREE_CODE (ref2) != COMPONENT_REF) | |
1960 | continue; | |
1961 | ||
1962 | /* The zeroth operand of the two component references must be | |
1963 | identical. It is not sufficient to compare get_base_address of | |
1964 | the two references, because this could allow for different | |
1965 | elements of the same array in the two trees. It is not safe to | |
1966 | assume that the existence of one array element implies the | |
1967 | existence of a different one. */ | |
1968 | if (!operand_equal_p (TREE_OPERAND (ref1, 0), TREE_OPERAND (ref2, 0), 0)) | |
1969 | continue; | |
1970 | ||
1971 | field1 = TREE_OPERAND (ref1, 1); | |
1972 | field2 = TREE_OPERAND (ref2, 1); | |
1973 | ||
1974 | /* Check for field adjacency, and ensure field1 comes first. */ | |
1975 | for (next = DECL_CHAIN (field1); | |
1976 | next && TREE_CODE (next) != FIELD_DECL; | |
1977 | next = DECL_CHAIN (next)) | |
1978 | ; | |
1979 | ||
1980 | if (next != field2) | |
1981 | { | |
1982 | for (next = DECL_CHAIN (field2); | |
1983 | next && TREE_CODE (next) != FIELD_DECL; | |
1984 | next = DECL_CHAIN (next)) | |
1985 | ; | |
1986 | ||
1987 | if (next != field1) | |
1988 | continue; | |
1989 | ||
1990 | fieldswap = field1; | |
1991 | field1 = field2; | |
1992 | field2 = fieldswap; | |
1993 | defswap = def1; | |
1994 | def1 = def2; | |
1995 | def2 = defswap; | |
372a6eb8 BS |
1996 | } |
1997 | ||
9b10be32 BS |
1998 | bb_for_def1 = gimple_bb (def1); |
1999 | bb_for_def2 = gimple_bb (def2); | |
2000 | ||
372a6eb8 BS |
2001 | /* Check for proper alignment of the first field. */ |
2002 | tree_offset1 = bit_position (field1); | |
2003 | tree_offset2 = bit_position (field2); | |
2004 | tree_size2 = DECL_SIZE (field2); | |
2005 | ||
cc269bb6 RS |
2006 | if (!tree_fits_uhwi_p (tree_offset1) |
2007 | || !tree_fits_uhwi_p (tree_offset2) | |
2008 | || !tree_fits_uhwi_p (tree_size2)) | |
372a6eb8 BS |
2009 | continue; |
2010 | ||
eb1ce453 KZ |
2011 | offset1 = tree_to_uhwi (tree_offset1); |
2012 | offset2 = tree_to_uhwi (tree_offset2); | |
2013 | size2 = tree_to_uhwi (tree_size2); | |
372a6eb8 BS |
2014 | align1 = DECL_ALIGN (field1) % param_align_bits; |
2015 | ||
2016 | if (offset1 % BITS_PER_UNIT != 0) | |
2017 | continue; | |
2018 | ||
2019 | /* For profitability, the two field references should fit within | |
2020 | a single cache line. */ | |
2021 | if (align1 + offset2 - offset1 + size2 > param_align_bits) | |
2022 | continue; | |
2023 | ||
2024 | /* The two expressions cannot be dependent upon vdefs defined | |
2025 | in bb1/bb2. */ | |
2026 | if (local_mem_dependence (def1, bb_for_def1) | |
2027 | || local_mem_dependence (def2, bb_for_def2)) | |
2028 | continue; | |
2029 | ||
2030 | /* The conditions are satisfied; hoist the loads from bb1 and bb2 into | |
2031 | bb0. We hoist the first one first so that a cache miss is handled | |
2032 | efficiently regardless of hardware cache-fill policy. */ | |
2033 | gsi2 = gsi_for_stmt (def1); | |
2034 | gsi_move_to_bb_end (&gsi2, bb0); | |
2035 | gsi2 = gsi_for_stmt (def2); | |
2036 | gsi_move_to_bb_end (&gsi2, bb0); | |
2037 | ||
2038 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2039 | { | |
2040 | fprintf (dump_file, | |
2041 | "\nHoisting adjacent loads from %d and %d into %d: \n", | |
2042 | bb_for_def1->index, bb_for_def2->index, bb0->index); | |
2043 | print_gimple_stmt (dump_file, def1, 0, TDF_VOPS|TDF_MEMSYMS); | |
2044 | print_gimple_stmt (dump_file, def2, 0, TDF_VOPS|TDF_MEMSYMS); | |
2045 | } | |
2046 | } | |
2047 | } | |
2048 | ||
2049 | /* Determine whether we should attempt to hoist adjacent loads out of | |
2050 | diamond patterns in pass_phiopt. Always hoist loads if | |
2051 | -fhoist-adjacent-loads is specified and the target machine has | |
7ef58a1a | 2052 | both a conditional move instruction and a defined cache line size. */ |
372a6eb8 BS |
2053 | |
2054 | static bool | |
2055 | gate_hoist_loads (void) | |
2056 | { | |
7ef58a1a BS |
2057 | return (flag_hoist_adjacent_loads == 1 |
2058 | && PARAM_VALUE (PARAM_L1_CACHE_LINE_SIZE) | |
2059 | && HAVE_conditional_move); | |
372a6eb8 BS |
2060 | } |
2061 | ||
be55bfe6 TS |
2062 | /* This pass tries to replaces an if-then-else block with an |
2063 | assignment. We have four kinds of transformations. Some of these | |
2064 | transformations are also performed by the ifcvt RTL optimizer. | |
2065 | ||
2066 | Conditional Replacement | |
2067 | ----------------------- | |
2068 | ||
2069 | This transformation, implemented in conditional_replacement, | |
2070 | replaces | |
2071 | ||
2072 | bb0: | |
2073 | if (cond) goto bb2; else goto bb1; | |
2074 | bb1: | |
2075 | bb2: | |
2076 | x = PHI <0 (bb1), 1 (bb0), ...>; | |
2077 | ||
2078 | with | |
2079 | ||
2080 | bb0: | |
2081 | x' = cond; | |
2082 | goto bb2; | |
2083 | bb2: | |
2084 | x = PHI <x' (bb0), ...>; | |
2085 | ||
2086 | We remove bb1 as it becomes unreachable. This occurs often due to | |
2087 | gimplification of conditionals. | |
2088 | ||
2089 | Value Replacement | |
2090 | ----------------- | |
2091 | ||
2092 | This transformation, implemented in value_replacement, replaces | |
2093 | ||
2094 | bb0: | |
2095 | if (a != b) goto bb2; else goto bb1; | |
2096 | bb1: | |
2097 | bb2: | |
2098 | x = PHI <a (bb1), b (bb0), ...>; | |
2099 | ||
2100 | with | |
2101 | ||
2102 | bb0: | |
2103 | bb2: | |
2104 | x = PHI <b (bb0), ...>; | |
2105 | ||
2106 | This opportunity can sometimes occur as a result of other | |
2107 | optimizations. | |
2108 | ||
2109 | ||
2110 | Another case caught by value replacement looks like this: | |
2111 | ||
2112 | bb0: | |
2113 | t1 = a == CONST; | |
2114 | t2 = b > c; | |
2115 | t3 = t1 & t2; | |
2116 | if (t3 != 0) goto bb1; else goto bb2; | |
2117 | bb1: | |
2118 | bb2: | |
2119 | x = PHI (CONST, a) | |
2120 | ||
2121 | Gets replaced with: | |
2122 | bb0: | |
2123 | bb2: | |
2124 | t1 = a == CONST; | |
2125 | t2 = b > c; | |
2126 | t3 = t1 & t2; | |
2127 | x = a; | |
2128 | ||
2129 | ABS Replacement | |
2130 | --------------- | |
2131 | ||
2132 | This transformation, implemented in abs_replacement, replaces | |
2133 | ||
2134 | bb0: | |
2135 | if (a >= 0) goto bb2; else goto bb1; | |
2136 | bb1: | |
2137 | x = -a; | |
2138 | bb2: | |
2139 | x = PHI <x (bb1), a (bb0), ...>; | |
2140 | ||
2141 | with | |
2142 | ||
2143 | bb0: | |
2144 | x' = ABS_EXPR< a >; | |
2145 | bb2: | |
2146 | x = PHI <x' (bb0), ...>; | |
2147 | ||
2148 | MIN/MAX Replacement | |
2149 | ------------------- | |
2150 | ||
2151 | This transformation, minmax_replacement replaces | |
2152 | ||
2153 | bb0: | |
2154 | if (a <= b) goto bb2; else goto bb1; | |
2155 | bb1: | |
2156 | bb2: | |
2157 | x = PHI <b (bb1), a (bb0), ...>; | |
2158 | ||
2159 | with | |
2160 | ||
2161 | bb0: | |
2162 | x' = MIN_EXPR (a, b) | |
2163 | bb2: | |
2164 | x = PHI <x' (bb0), ...>; | |
2165 | ||
2166 | A similar transformation is done for MAX_EXPR. | |
2167 | ||
2168 | ||
2169 | This pass also performs a fifth transformation of a slightly different | |
2170 | flavor. | |
2171 | ||
2172 | Adjacent Load Hoisting | |
2173 | ---------------------- | |
2174 | ||
2175 | This transformation replaces | |
2176 | ||
2177 | bb0: | |
2178 | if (...) goto bb2; else goto bb1; | |
2179 | bb1: | |
2180 | x1 = (<expr>).field1; | |
2181 | goto bb3; | |
2182 | bb2: | |
2183 | x2 = (<expr>).field2; | |
2184 | bb3: | |
2185 | # x = PHI <x1, x2>; | |
2186 | ||
2187 | with | |
2188 | ||
2189 | bb0: | |
2190 | x1 = (<expr>).field1; | |
2191 | x2 = (<expr>).field2; | |
2192 | if (...) goto bb2; else goto bb1; | |
2193 | bb1: | |
2194 | goto bb3; | |
2195 | bb2: | |
2196 | bb3: | |
2197 | # x = PHI <x1, x2>; | |
2198 | ||
2199 | The purpose of this transformation is to enable generation of conditional | |
2200 | move instructions such as Intel CMOVE or PowerPC ISEL. Because one of | |
2201 | the loads is speculative, the transformation is restricted to very | |
2202 | specific cases to avoid introducing a page fault. We are looking for | |
2203 | the common idiom: | |
2204 | ||
2205 | if (...) | |
2206 | x = y->left; | |
2207 | else | |
2208 | x = y->right; | |
2209 | ||
2210 | where left and right are typically adjacent pointers in a tree structure. */ | |
0385f644 | 2211 | |
27a4cd48 DM |
2212 | namespace { |
2213 | ||
2214 | const pass_data pass_data_phiopt = | |
6de9cd9a | 2215 | { |
27a4cd48 DM |
2216 | GIMPLE_PASS, /* type */ |
2217 | "phiopt", /* name */ | |
2218 | OPTGROUP_NONE, /* optinfo_flags */ | |
27a4cd48 DM |
2219 | TV_TREE_PHIOPT, /* tv_id */ |
2220 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
2221 | 0, /* properties_provided */ | |
2222 | 0, /* properties_destroyed */ | |
2223 | 0, /* todo_flags_start */ | |
3bea341f | 2224 | 0, /* todo_flags_finish */ |
6de9cd9a | 2225 | }; |
a5828d1e | 2226 | |
27a4cd48 DM |
2227 | class pass_phiopt : public gimple_opt_pass |
2228 | { | |
2229 | public: | |
c3284718 RS |
2230 | pass_phiopt (gcc::context *ctxt) |
2231 | : gimple_opt_pass (pass_data_phiopt, ctxt) | |
27a4cd48 DM |
2232 | {} |
2233 | ||
2234 | /* opt_pass methods: */ | |
65d3284b | 2235 | opt_pass * clone () { return new pass_phiopt (m_ctxt); } |
68f6df73 | 2236 | virtual bool gate (function *) { return flag_ssa_phiopt; } |
be55bfe6 TS |
2237 | virtual unsigned int execute (function *) |
2238 | { | |
2239 | return tree_ssa_phiopt_worker (false, gate_hoist_loads ()); | |
2240 | } | |
27a4cd48 DM |
2241 | |
2242 | }; // class pass_phiopt | |
2243 | ||
2244 | } // anon namespace | |
2245 | ||
2246 | gimple_opt_pass * | |
2247 | make_pass_phiopt (gcc::context *ctxt) | |
2248 | { | |
2249 | return new pass_phiopt (ctxt); | |
2250 | } | |
2251 | ||
27a4cd48 DM |
2252 | namespace { |
2253 | ||
2254 | const pass_data pass_data_cselim = | |
a5828d1e | 2255 | { |
27a4cd48 DM |
2256 | GIMPLE_PASS, /* type */ |
2257 | "cselim", /* name */ | |
2258 | OPTGROUP_NONE, /* optinfo_flags */ | |
27a4cd48 DM |
2259 | TV_TREE_PHIOPT, /* tv_id */ |
2260 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
2261 | 0, /* properties_provided */ | |
2262 | 0, /* properties_destroyed */ | |
2263 | 0, /* todo_flags_start */ | |
3bea341f | 2264 | 0, /* todo_flags_finish */ |
a5828d1e | 2265 | }; |
27a4cd48 DM |
2266 | |
2267 | class pass_cselim : public gimple_opt_pass | |
2268 | { | |
2269 | public: | |
c3284718 RS |
2270 | pass_cselim (gcc::context *ctxt) |
2271 | : gimple_opt_pass (pass_data_cselim, ctxt) | |
27a4cd48 DM |
2272 | {} |
2273 | ||
2274 | /* opt_pass methods: */ | |
1a3d085c | 2275 | virtual bool gate (function *) { return flag_tree_cselim; } |
be55bfe6 | 2276 | virtual unsigned int execute (function *) { return tree_ssa_cs_elim (); } |
27a4cd48 DM |
2277 | |
2278 | }; // class pass_cselim | |
2279 | ||
2280 | } // anon namespace | |
2281 | ||
2282 | gimple_opt_pass * | |
2283 | make_pass_cselim (gcc::context *ctxt) | |
2284 | { | |
2285 | return new pass_cselim (ctxt); | |
2286 | } |