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4ee9c684 | 1 | /* Optimization of PHI nodes by converting them into straightline code. |
3aea1f79 | 2 | Copyright (C) 2004-2014 Free Software Foundation, Inc. |
4ee9c684 | 3 | |
4 | This file is part of GCC. | |
20e5647c | 5 | |
4ee9c684 | 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 | |
8c4c00c1 | 8 | Free Software Foundation; either version 3, or (at your option) any |
4ee9c684 | 9 | later version. |
20e5647c | 10 | |
4ee9c684 | 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. | |
20e5647c | 15 | |
4ee9c684 | 16 | You should have received a copy of the GNU General Public License |
8c4c00c1 | 17 | along with GCC; see the file COPYING3. If not see |
18 | <http://www.gnu.org/licenses/>. */ | |
4ee9c684 | 19 | |
20 | #include "config.h" | |
21 | #include "system.h" | |
22 | #include "coretypes.h" | |
d9dd21a8 | 23 | #include "hash-table.h" |
4ee9c684 | 24 | #include "tm.h" |
4ee9c684 | 25 | #include "tree.h" |
9ed99284 | 26 | #include "stor-layout.h" |
0beac6fc | 27 | #include "flags.h" |
4ee9c684 | 28 | #include "tm_p.h" |
29 | #include "basic-block.h" | |
bc61cadb | 30 | #include "pointer-set.h" |
31 | #include "tree-ssa-alias.h" | |
32 | #include "internal-fn.h" | |
33 | #include "gimple-expr.h" | |
34 | #include "is-a.h" | |
073c1fd5 | 35 | #include "gimple.h" |
a8783bee | 36 | #include "gimplify.h" |
dcf1a1ec | 37 | #include "gimple-iterator.h" |
e795d6e1 | 38 | #include "gimplify-me.h" |
073c1fd5 | 39 | #include "gimple-ssa.h" |
40 | #include "tree-cfg.h" | |
41 | #include "tree-phinodes.h" | |
42 | #include "ssa-iterators.h" | |
9ed99284 | 43 | #include "stringpool.h" |
073c1fd5 | 44 | #include "tree-ssanames.h" |
9ed99284 | 45 | #include "expr.h" |
073c1fd5 | 46 | #include "tree-dfa.h" |
4ee9c684 | 47 | #include "tree-pass.h" |
4ee9c684 | 48 | #include "langhooks.h" |
e6d0e152 | 49 | #include "domwalk.h" |
ec611e12 | 50 | #include "cfgloop.h" |
51 | #include "tree-data-ref.h" | |
239e9670 | 52 | #include "gimple-pretty-print.h" |
53 | #include "insn-config.h" | |
54 | #include "expr.h" | |
55 | #include "optabs.h" | |
f6568ea4 | 56 | #include "tree-scalar-evolution.h" |
b6814ca0 | 57 | #include "tree-inline.h" |
239e9670 | 58 | |
59 | #ifndef HAVE_conditional_move | |
60 | #define HAVE_conditional_move (0) | |
61 | #endif | |
4ee9c684 | 62 | |
239e9670 | 63 | static unsigned int tree_ssa_phiopt_worker (bool, bool); |
a4844041 | 64 | static bool conditional_replacement (basic_block, basic_block, |
75a70cf9 | 65 | edge, edge, gimple, tree, tree); |
fb9912ea | 66 | static int value_replacement (basic_block, basic_block, |
67 | edge, edge, gimple, tree, tree); | |
a4844041 | 68 | static bool minmax_replacement (basic_block, basic_block, |
75a70cf9 | 69 | edge, edge, gimple, tree, tree); |
a4844041 | 70 | static bool abs_replacement (basic_block, basic_block, |
75a70cf9 | 71 | edge, edge, gimple, tree, tree); |
88747429 | 72 | static bool neg_replacement (basic_block, basic_block, |
73 | edge, edge, gimple, tree, tree); | |
e6d0e152 | 74 | static bool cond_store_replacement (basic_block, basic_block, edge, edge, |
75 | struct pointer_set_t *); | |
91cf53d5 | 76 | static bool cond_if_else_store_replacement (basic_block, basic_block, basic_block); |
e6d0e152 | 77 | static struct pointer_set_t * get_non_trapping (void); |
75a70cf9 | 78 | static void replace_phi_edge_with_variable (basic_block, edge, gimple, tree); |
239e9670 | 79 | static void hoist_adjacent_loads (basic_block, basic_block, |
80 | basic_block, basic_block); | |
81 | static bool gate_hoist_loads (void); | |
902929aa | 82 | |
e6d0e152 | 83 | /* This pass tries to transform conditional stores into unconditional |
84 | ones, enabling further simplifications with the simpler then and else | |
85 | blocks. In particular it replaces this: | |
86 | ||
87 | bb0: | |
88 | if (cond) goto bb2; else goto bb1; | |
89 | bb1: | |
91cf53d5 | 90 | *p = RHS; |
e6d0e152 | 91 | bb2: |
92 | ||
93 | with | |
94 | ||
95 | bb0: | |
96 | if (cond) goto bb1; else goto bb2; | |
97 | bb1: | |
98 | condtmp' = *p; | |
99 | bb2: | |
100 | condtmp = PHI <RHS, condtmp'> | |
91cf53d5 | 101 | *p = condtmp; |
e6d0e152 | 102 | |
103 | This transformation can only be done under several constraints, | |
91cf53d5 | 104 | documented below. It also replaces: |
105 | ||
106 | bb0: | |
107 | if (cond) goto bb2; else goto bb1; | |
108 | bb1: | |
109 | *p = RHS1; | |
110 | goto bb3; | |
111 | bb2: | |
112 | *p = RHS2; | |
113 | bb3: | |
114 | ||
115 | with | |
116 | ||
117 | bb0: | |
118 | if (cond) goto bb3; else goto bb1; | |
119 | bb1: | |
120 | bb3: | |
121 | condtmp = PHI <RHS1, RHS2> | |
122 | *p = condtmp; */ | |
e6d0e152 | 123 | |
124 | static unsigned int | |
125 | tree_ssa_cs_elim (void) | |
126 | { | |
f6568ea4 | 127 | unsigned todo; |
128 | /* ??? We are not interested in loop related info, but the following | |
129 | will create it, ICEing as we didn't init loops with pre-headers. | |
130 | An interfacing issue of find_data_references_in_bb. */ | |
131 | loop_optimizer_init (LOOPS_NORMAL); | |
132 | scev_initialize (); | |
133 | todo = tree_ssa_phiopt_worker (true, false); | |
134 | scev_finalize (); | |
135 | loop_optimizer_finalize (); | |
136 | return todo; | |
e6d0e152 | 137 | } |
138 | ||
c3597b05 | 139 | /* Return the singleton PHI in the SEQ of PHIs for edges E0 and E1. */ |
140 | ||
141 | static gimple | |
142 | single_non_singleton_phi_for_edges (gimple_seq seq, edge e0, edge e1) | |
143 | { | |
144 | gimple_stmt_iterator i; | |
145 | gimple phi = NULL; | |
146 | if (gimple_seq_singleton_p (seq)) | |
147 | return gsi_stmt (gsi_start (seq)); | |
148 | for (i = gsi_start (seq); !gsi_end_p (i); gsi_next (&i)) | |
149 | { | |
150 | gimple p = gsi_stmt (i); | |
151 | /* If the PHI arguments are equal then we can skip this PHI. */ | |
152 | if (operand_equal_for_phi_arg_p (gimple_phi_arg_def (p, e0->dest_idx), | |
153 | gimple_phi_arg_def (p, e1->dest_idx))) | |
154 | continue; | |
155 | ||
156 | /* If we already have a PHI that has the two edge arguments are | |
157 | different, then return it is not a singleton for these PHIs. */ | |
158 | if (phi) | |
159 | return NULL; | |
160 | ||
161 | phi = p; | |
162 | } | |
163 | return phi; | |
164 | } | |
165 | ||
e6d0e152 | 166 | /* The core routine of conditional store replacement and normal |
167 | phi optimizations. Both share much of the infrastructure in how | |
168 | to match applicable basic block patterns. DO_STORE_ELIM is true | |
239e9670 | 169 | when we want to do conditional store replacement, false otherwise. |
f32420fb | 170 | DO_HOIST_LOADS is true when we want to hoist adjacent loads out |
239e9670 | 171 | of diamond control flow patterns, false otherwise. */ |
e6d0e152 | 172 | static unsigned int |
239e9670 | 173 | tree_ssa_phiopt_worker (bool do_store_elim, bool do_hoist_loads) |
4ee9c684 | 174 | { |
175 | basic_block bb; | |
194899bf | 176 | basic_block *bb_order; |
177 | unsigned n, i; | |
1e4b21e3 | 178 | bool cfgchanged = false; |
e6d0e152 | 179 | struct pointer_set_t *nontrap = 0; |
180 | ||
181 | if (do_store_elim) | |
03d37e4e | 182 | /* Calculate the set of non-trapping memory accesses. */ |
183 | nontrap = get_non_trapping (); | |
194899bf | 184 | |
88747429 | 185 | /* The replacement of conditional negation with a non-branching |
186 | sequence is really only a win when optimizing for speed and we | |
187 | can avoid transformations by gimple if-conversion that result | |
188 | in poor RTL generation. | |
189 | ||
190 | Ideally either gimple if-conversion or the RTL expanders will | |
191 | be improved and the code to emit branchless conditional negation | |
192 | can be removed. */ | |
193 | bool replace_conditional_negation = false; | |
194 | if (!do_store_elim) | |
195 | replace_conditional_negation | |
196 | = ((!optimize_size && optimize >= 2) | |
4c73695b | 197 | || (((flag_tree_loop_vectorize || cfun->has_force_vectorize_loops) |
88747429 | 198 | && flag_tree_loop_if_convert != 0) |
199 | || flag_tree_loop_if_convert == 1 | |
200 | || flag_tree_loop_if_convert_stores == 1)); | |
201 | ||
194899bf | 202 | /* Search every basic block for COND_EXPR we may be able to optimize. |
203 | ||
204 | We walk the blocks in order that guarantees that a block with | |
205 | a single predecessor is processed before the predecessor. | |
206 | This ensures that we collapse inner ifs before visiting the | |
207 | outer ones, and also that we do not try to visit a removed | |
208 | block. */ | |
ba4d2b2f | 209 | bb_order = single_pred_before_succ_order (); |
a28770e1 | 210 | n = n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS; |
4ee9c684 | 211 | |
48e1416a | 212 | for (i = 0; i < n; i++) |
4ee9c684 | 213 | { |
75a70cf9 | 214 | gimple cond_stmt, phi; |
33784d89 | 215 | basic_block bb1, bb2; |
216 | edge e1, e2; | |
194899bf | 217 | tree arg0, arg1; |
218 | ||
219 | bb = bb_order[i]; | |
20e5647c | 220 | |
75a70cf9 | 221 | cond_stmt = last_stmt (bb); |
222 | /* Check to see if the last statement is a GIMPLE_COND. */ | |
223 | if (!cond_stmt | |
224 | || gimple_code (cond_stmt) != GIMPLE_COND) | |
33784d89 | 225 | continue; |
20e5647c | 226 | |
33784d89 | 227 | e1 = EDGE_SUCC (bb, 0); |
228 | bb1 = e1->dest; | |
229 | e2 = EDGE_SUCC (bb, 1); | |
230 | bb2 = e2->dest; | |
20e5647c | 231 | |
33784d89 | 232 | /* We cannot do the optimization on abnormal edges. */ |
233 | if ((e1->flags & EDGE_ABNORMAL) != 0 | |
234 | || (e2->flags & EDGE_ABNORMAL) != 0) | |
235 | continue; | |
20e5647c | 236 | |
33784d89 | 237 | /* If either bb1's succ or bb2 or bb2's succ is non NULL. */ |
ea091dfd | 238 | if (EDGE_COUNT (bb1->succs) == 0 |
33784d89 | 239 | || bb2 == NULL |
ea091dfd | 240 | || EDGE_COUNT (bb2->succs) == 0) |
33784d89 | 241 | continue; |
20e5647c | 242 | |
33784d89 | 243 | /* Find the bb which is the fall through to the other. */ |
244 | if (EDGE_SUCC (bb1, 0)->dest == bb2) | |
245 | ; | |
246 | else if (EDGE_SUCC (bb2, 0)->dest == bb1) | |
247 | { | |
248 | basic_block bb_tmp = bb1; | |
249 | edge e_tmp = e1; | |
250 | bb1 = bb2; | |
251 | bb2 = bb_tmp; | |
252 | e1 = e2; | |
253 | e2 = e_tmp; | |
254 | } | |
91cf53d5 | 255 | else if (do_store_elim |
256 | && EDGE_SUCC (bb1, 0)->dest == EDGE_SUCC (bb2, 0)->dest) | |
257 | { | |
258 | basic_block bb3 = EDGE_SUCC (bb1, 0)->dest; | |
259 | ||
260 | if (!single_succ_p (bb1) | |
261 | || (EDGE_SUCC (bb1, 0)->flags & EDGE_FALLTHRU) == 0 | |
262 | || !single_succ_p (bb2) | |
263 | || (EDGE_SUCC (bb2, 0)->flags & EDGE_FALLTHRU) == 0 | |
264 | || EDGE_COUNT (bb3->preds) != 2) | |
265 | continue; | |
266 | if (cond_if_else_store_replacement (bb1, bb2, bb3)) | |
267 | cfgchanged = true; | |
268 | continue; | |
269 | } | |
239e9670 | 270 | else if (do_hoist_loads |
271 | && EDGE_SUCC (bb1, 0)->dest == EDGE_SUCC (bb2, 0)->dest) | |
272 | { | |
273 | basic_block bb3 = EDGE_SUCC (bb1, 0)->dest; | |
274 | ||
275 | if (!FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (cond_stmt))) | |
276 | && single_succ_p (bb1) | |
277 | && single_succ_p (bb2) | |
278 | && single_pred_p (bb1) | |
279 | && single_pred_p (bb2) | |
280 | && EDGE_COUNT (bb->succs) == 2 | |
281 | && EDGE_COUNT (bb3->preds) == 2 | |
282 | /* If one edge or the other is dominant, a conditional move | |
283 | is likely to perform worse than the well-predicted branch. */ | |
284 | && !predictable_edge_p (EDGE_SUCC (bb, 0)) | |
285 | && !predictable_edge_p (EDGE_SUCC (bb, 1))) | |
286 | hoist_adjacent_loads (bb, bb1, bb2, bb3); | |
287 | continue; | |
288 | } | |
33784d89 | 289 | else |
f32420fb | 290 | continue; |
20e5647c | 291 | |
33784d89 | 292 | e1 = EDGE_SUCC (bb1, 0); |
20e5647c | 293 | |
33784d89 | 294 | /* Make sure that bb1 is just a fall through. */ |
db5ba14c | 295 | if (!single_succ_p (bb1) |
33784d89 | 296 | || (e1->flags & EDGE_FALLTHRU) == 0) |
297 | continue; | |
20e5647c | 298 | |
3472707f | 299 | /* Also make sure that bb1 only have one predecessor and that it |
300 | is bb. */ | |
ea091dfd | 301 | if (!single_pred_p (bb1) |
302 | || single_pred (bb1) != bb) | |
33784d89 | 303 | continue; |
20e5647c | 304 | |
e6d0e152 | 305 | if (do_store_elim) |
306 | { | |
307 | /* bb1 is the middle block, bb2 the join block, bb the split block, | |
308 | e1 the fallthrough edge from bb1 to bb2. We can't do the | |
309 | optimization if the join block has more than two predecessors. */ | |
310 | if (EDGE_COUNT (bb2->preds) > 2) | |
311 | continue; | |
312 | if (cond_store_replacement (bb1, bb2, e1, e2, nontrap)) | |
313 | cfgchanged = true; | |
314 | } | |
315 | else | |
316 | { | |
75a70cf9 | 317 | gimple_seq phis = phi_nodes (bb2); |
2109076a | 318 | gimple_stmt_iterator gsi; |
fb9912ea | 319 | bool candorest = true; |
c3597b05 | 320 | |
fb9912ea | 321 | /* Value replacement can work with more than one PHI |
322 | so try that first. */ | |
323 | for (gsi = gsi_start (phis); !gsi_end_p (gsi); gsi_next (&gsi)) | |
324 | { | |
325 | phi = gsi_stmt (gsi); | |
326 | arg0 = gimple_phi_arg_def (phi, e1->dest_idx); | |
327 | arg1 = gimple_phi_arg_def (phi, e2->dest_idx); | |
328 | if (value_replacement (bb, bb1, e1, e2, phi, arg0, arg1) == 2) | |
329 | { | |
330 | candorest = false; | |
331 | cfgchanged = true; | |
332 | break; | |
333 | } | |
334 | } | |
e6d0e152 | 335 | |
fb9912ea | 336 | if (!candorest) |
337 | continue; | |
f32420fb | 338 | |
c3597b05 | 339 | phi = single_non_singleton_phi_for_edges (phis, e1, e2); |
2109076a | 340 | if (!phi) |
e6d0e152 | 341 | continue; |
342 | ||
75a70cf9 | 343 | arg0 = gimple_phi_arg_def (phi, e1->dest_idx); |
344 | arg1 = gimple_phi_arg_def (phi, e2->dest_idx); | |
e6d0e152 | 345 | |
346 | /* Something is wrong if we cannot find the arguments in the PHI | |
347 | node. */ | |
348 | gcc_assert (arg0 != NULL && arg1 != NULL); | |
349 | ||
350 | /* Do the replacement of conditional if it can be done. */ | |
351 | if (conditional_replacement (bb, bb1, e1, e2, phi, arg0, arg1)) | |
352 | cfgchanged = true; | |
e6d0e152 | 353 | else if (abs_replacement (bb, bb1, e1, e2, phi, arg0, arg1)) |
354 | cfgchanged = true; | |
88747429 | 355 | else if (replace_conditional_negation |
356 | && neg_replacement (bb, bb1, e1, e2, phi, arg0, arg1)) | |
357 | cfgchanged = true; | |
e6d0e152 | 358 | else if (minmax_replacement (bb, bb1, e1, e2, phi, arg0, arg1)) |
359 | cfgchanged = true; | |
360 | } | |
194899bf | 361 | } |
362 | ||
363 | free (bb_order); | |
48e1416a | 364 | |
e6d0e152 | 365 | if (do_store_elim) |
366 | pointer_set_destroy (nontrap); | |
367 | /* If the CFG has changed, we should cleanup the CFG. */ | |
368 | if (cfgchanged && do_store_elim) | |
369 | { | |
370 | /* In cond-store replacement we have added some loads on edges | |
371 | and new VOPS (as we moved the store, and created a load). */ | |
75a70cf9 | 372 | gsi_commit_edge_inserts (); |
e6d0e152 | 373 | return TODO_cleanup_cfg | TODO_update_ssa_only_virtuals; |
374 | } | |
375 | else if (cfgchanged) | |
376 | return TODO_cleanup_cfg; | |
377 | return 0; | |
194899bf | 378 | } |
379 | ||
fccee353 | 380 | /* Replace PHI node element whose edge is E in block BB with variable NEW. |
33784d89 | 381 | Remove the edge from COND_BLOCK which does not lead to BB (COND_BLOCK |
902929aa | 382 | is known to have two edges, one of which must reach BB). */ |
383 | ||
384 | static void | |
a4844041 | 385 | replace_phi_edge_with_variable (basic_block cond_block, |
75a70cf9 | 386 | edge e, gimple phi, tree new_tree) |
902929aa | 387 | { |
75a70cf9 | 388 | basic_block bb = gimple_bb (phi); |
0e1a77e1 | 389 | basic_block block_to_remove; |
75a70cf9 | 390 | gimple_stmt_iterator gsi; |
33784d89 | 391 | |
20e5647c | 392 | /* Change the PHI argument to new. */ |
f0d6e81c | 393 | SET_USE (PHI_ARG_DEF_PTR (phi, e->dest_idx), new_tree); |
0e1a77e1 | 394 | |
0e1a77e1 | 395 | /* Remove the empty basic block. */ |
cd665a06 | 396 | if (EDGE_SUCC (cond_block, 0)->dest == bb) |
902929aa | 397 | { |
cd665a06 | 398 | EDGE_SUCC (cond_block, 0)->flags |= EDGE_FALLTHRU; |
399 | EDGE_SUCC (cond_block, 0)->flags &= ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE); | |
81c5be57 | 400 | EDGE_SUCC (cond_block, 0)->probability = REG_BR_PROB_BASE; |
401 | EDGE_SUCC (cond_block, 0)->count += EDGE_SUCC (cond_block, 1)->count; | |
0e1a77e1 | 402 | |
cd665a06 | 403 | block_to_remove = EDGE_SUCC (cond_block, 1)->dest; |
902929aa | 404 | } |
405 | else | |
406 | { | |
cd665a06 | 407 | EDGE_SUCC (cond_block, 1)->flags |= EDGE_FALLTHRU; |
408 | EDGE_SUCC (cond_block, 1)->flags | |
902929aa | 409 | &= ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE); |
81c5be57 | 410 | EDGE_SUCC (cond_block, 1)->probability = REG_BR_PROB_BASE; |
411 | EDGE_SUCC (cond_block, 1)->count += EDGE_SUCC (cond_block, 0)->count; | |
0e1a77e1 | 412 | |
cd665a06 | 413 | block_to_remove = EDGE_SUCC (cond_block, 0)->dest; |
902929aa | 414 | } |
0e1a77e1 | 415 | delete_basic_block (block_to_remove); |
20e5647c | 416 | |
902929aa | 417 | /* Eliminate the COND_EXPR at the end of COND_BLOCK. */ |
75a70cf9 | 418 | gsi = gsi_last_bb (cond_block); |
419 | gsi_remove (&gsi, true); | |
20e5647c | 420 | |
902929aa | 421 | if (dump_file && (dump_flags & TDF_DETAILS)) |
422 | fprintf (dump_file, | |
423 | "COND_EXPR in block %d and PHI in block %d converted to straightline code.\n", | |
424 | cond_block->index, | |
425 | bb->index); | |
426 | } | |
427 | ||
428 | /* The function conditional_replacement does the main work of doing the | |
429 | conditional replacement. Return true if the replacement is done. | |
430 | Otherwise return false. | |
431 | BB is the basic block where the replacement is going to be done on. ARG0 | |
dac49aa5 | 432 | is argument 0 from PHI. Likewise for ARG1. */ |
902929aa | 433 | |
434 | static bool | |
33784d89 | 435 | conditional_replacement (basic_block cond_bb, basic_block middle_bb, |
75a70cf9 | 436 | edge e0, edge e1, gimple phi, |
33784d89 | 437 | tree arg0, tree arg1) |
902929aa | 438 | { |
439 | tree result; | |
75a70cf9 | 440 | gimple stmt, new_stmt; |
441 | tree cond; | |
442 | gimple_stmt_iterator gsi; | |
902929aa | 443 | edge true_edge, false_edge; |
75a70cf9 | 444 | tree new_var, new_var2; |
678919fd | 445 | bool neg; |
902929aa | 446 | |
435e1a75 | 447 | /* FIXME: Gimplification of complex type is too hard for now. */ |
47b88316 | 448 | /* We aren't prepared to handle vectors either (and it is a question |
449 | if it would be worthwhile anyway). */ | |
450 | if (!(INTEGRAL_TYPE_P (TREE_TYPE (arg0)) | |
451 | || POINTER_TYPE_P (TREE_TYPE (arg0))) | |
452 | || !(INTEGRAL_TYPE_P (TREE_TYPE (arg1)) | |
453 | || POINTER_TYPE_P (TREE_TYPE (arg1)))) | |
435e1a75 | 454 | return false; |
455 | ||
678919fd | 456 | /* The PHI arguments have the constants 0 and 1, or 0 and -1, then |
457 | convert it to the conditional. */ | |
902929aa | 458 | if ((integer_zerop (arg0) && integer_onep (arg1)) |
459 | || (integer_zerop (arg1) && integer_onep (arg0))) | |
678919fd | 460 | neg = false; |
461 | else if ((integer_zerop (arg0) && integer_all_onesp (arg1)) | |
462 | || (integer_zerop (arg1) && integer_all_onesp (arg0))) | |
463 | neg = true; | |
902929aa | 464 | else |
465 | return false; | |
20e5647c | 466 | |
33784d89 | 467 | if (!empty_block_p (middle_bb)) |
902929aa | 468 | return false; |
20e5647c | 469 | |
75a70cf9 | 470 | /* At this point we know we have a GIMPLE_COND with two successors. |
2ab0a163 | 471 | One successor is BB, the other successor is an empty block which |
472 | falls through into BB. | |
20e5647c | 473 | |
2ab0a163 | 474 | There is a single PHI node at the join point (BB) and its arguments |
678919fd | 475 | are constants (0, 1) or (0, -1). |
20e5647c | 476 | |
2ab0a163 | 477 | So, given the condition COND, and the two PHI arguments, we can |
20e5647c | 478 | rewrite this PHI into non-branching code: |
479 | ||
2ab0a163 | 480 | dest = (COND) or dest = COND' |
20e5647c | 481 | |
2ab0a163 | 482 | We use the condition as-is if the argument associated with the |
483 | true edge has the value one or the argument associated with the | |
484 | false edge as the value zero. Note that those conditions are not | |
75a70cf9 | 485 | the same since only one of the outgoing edges from the GIMPLE_COND |
2ab0a163 | 486 | will directly reach BB and thus be associated with an argument. */ |
ae5a4794 | 487 | |
75a70cf9 | 488 | stmt = last_stmt (cond_bb); |
489 | result = PHI_RESULT (phi); | |
b2a02a0e | 490 | |
75a70cf9 | 491 | /* To handle special cases like floating point comparison, it is easier and |
492 | less error-prone to build a tree and gimplify it on the fly though it is | |
493 | less efficient. */ | |
6f9714b3 | 494 | cond = fold_build2_loc (gimple_location (stmt), |
495 | gimple_cond_code (stmt), boolean_type_node, | |
496 | gimple_cond_lhs (stmt), gimple_cond_rhs (stmt)); | |
4ee9c684 | 497 | |
75a70cf9 | 498 | /* We need to know which is the true edge and which is the false |
499 | edge so that we know when to invert the condition below. */ | |
500 | extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge); | |
501 | if ((e0 == true_edge && integer_zerop (arg0)) | |
678919fd | 502 | || (e0 == false_edge && !integer_zerop (arg0)) |
75a70cf9 | 503 | || (e1 == true_edge && integer_zerop (arg1)) |
678919fd | 504 | || (e1 == false_edge && !integer_zerop (arg1))) |
6f9714b3 | 505 | cond = fold_build1_loc (gimple_location (stmt), |
678919fd | 506 | TRUTH_NOT_EXPR, TREE_TYPE (cond), cond); |
507 | ||
508 | if (neg) | |
509 | { | |
510 | cond = fold_convert_loc (gimple_location (stmt), | |
511 | TREE_TYPE (result), cond); | |
512 | cond = fold_build1_loc (gimple_location (stmt), | |
513 | NEGATE_EXPR, TREE_TYPE (cond), cond); | |
514 | } | |
75a70cf9 | 515 | |
516 | /* Insert our new statements at the end of conditional block before the | |
517 | COND_STMT. */ | |
518 | gsi = gsi_for_stmt (stmt); | |
519 | new_var = force_gimple_operand_gsi (&gsi, cond, true, NULL, true, | |
520 | GSI_SAME_STMT); | |
521 | ||
522 | if (!useless_type_conversion_p (TREE_TYPE (result), TREE_TYPE (new_var))) | |
523 | { | |
efbcb6de | 524 | source_location locus_0, locus_1; |
525 | ||
03d37e4e | 526 | new_var2 = make_ssa_name (TREE_TYPE (result), NULL); |
75a70cf9 | 527 | new_stmt = gimple_build_assign_with_ops (CONVERT_EXPR, new_var2, |
528 | new_var, NULL); | |
75a70cf9 | 529 | gsi_insert_before (&gsi, new_stmt, GSI_SAME_STMT); |
530 | new_var = new_var2; | |
efbcb6de | 531 | |
532 | /* Set the locus to the first argument, unless is doesn't have one. */ | |
533 | locus_0 = gimple_phi_arg_location (phi, 0); | |
534 | locus_1 = gimple_phi_arg_location (phi, 1); | |
535 | if (locus_0 == UNKNOWN_LOCATION) | |
536 | locus_0 = locus_1; | |
537 | gimple_set_location (new_stmt, locus_0); | |
4ee9c684 | 538 | } |
20e5647c | 539 | |
75a70cf9 | 540 | replace_phi_edge_with_variable (cond_bb, e1, phi, new_var); |
902929aa | 541 | |
4ee9c684 | 542 | /* Note that we optimized this PHI. */ |
543 | return true; | |
544 | } | |
545 | ||
17b9476e | 546 | /* Update *ARG which is defined in STMT so that it contains the |
547 | computed value if that seems profitable. Return true if the | |
548 | statement is made dead by that rewriting. */ | |
549 | ||
550 | static bool | |
551 | jump_function_from_stmt (tree *arg, gimple stmt) | |
552 | { | |
553 | enum tree_code code = gimple_assign_rhs_code (stmt); | |
554 | if (code == ADDR_EXPR) | |
555 | { | |
556 | /* For arg = &p->i transform it to p, if possible. */ | |
557 | tree rhs1 = gimple_assign_rhs1 (stmt); | |
558 | HOST_WIDE_INT offset; | |
559 | tree tem = get_addr_base_and_unit_offset (TREE_OPERAND (rhs1, 0), | |
560 | &offset); | |
561 | if (tem | |
562 | && TREE_CODE (tem) == MEM_REF | |
796b6678 | 563 | && (mem_ref_offset (tem) + offset) == 0) |
17b9476e | 564 | { |
565 | *arg = TREE_OPERAND (tem, 0); | |
566 | return true; | |
567 | } | |
568 | } | |
569 | /* TODO: Much like IPA-CP jump-functions we want to handle constant | |
570 | additions symbolically here, and we'd need to update the comparison | |
571 | code that compares the arg + cst tuples in our caller. For now the | |
572 | code above exactly handles the VEC_BASE pattern from vec.h. */ | |
573 | return false; | |
574 | } | |
575 | ||
f32420fb | 576 | /* RHS is a source argument in a BIT_AND_EXPR which feeds a conditional |
577 | of the form SSA_NAME NE 0. | |
578 | ||
579 | If RHS is fed by a simple EQ_EXPR comparison of two values, see if | |
580 | the two input values of the EQ_EXPR match arg0 and arg1. | |
581 | ||
582 | If so update *code and return TRUE. Otherwise return FALSE. */ | |
583 | ||
584 | static bool | |
585 | rhs_is_fed_for_value_replacement (const_tree arg0, const_tree arg1, | |
586 | enum tree_code *code, const_tree rhs) | |
587 | { | |
588 | /* Obviously if RHS is not an SSA_NAME, we can't look at the defining | |
589 | statement. */ | |
590 | if (TREE_CODE (rhs) == SSA_NAME) | |
591 | { | |
592 | gimple def1 = SSA_NAME_DEF_STMT (rhs); | |
593 | ||
594 | /* Verify the defining statement has an EQ_EXPR on the RHS. */ | |
595 | if (is_gimple_assign (def1) && gimple_assign_rhs_code (def1) == EQ_EXPR) | |
596 | { | |
597 | /* Finally verify the source operands of the EQ_EXPR are equal | |
598 | to arg0 and arg1. */ | |
599 | tree op0 = gimple_assign_rhs1 (def1); | |
600 | tree op1 = gimple_assign_rhs2 (def1); | |
601 | if ((operand_equal_for_phi_arg_p (arg0, op0) | |
602 | && operand_equal_for_phi_arg_p (arg1, op1)) | |
603 | || (operand_equal_for_phi_arg_p (arg0, op1) | |
604 | && operand_equal_for_phi_arg_p (arg1, op0))) | |
605 | { | |
606 | /* We will perform the optimization. */ | |
607 | *code = gimple_assign_rhs_code (def1); | |
608 | return true; | |
609 | } | |
610 | } | |
611 | } | |
612 | return false; | |
613 | } | |
614 | ||
615 | /* Return TRUE if arg0/arg1 are equal to the rhs/lhs or lhs/rhs of COND. | |
616 | ||
617 | Also return TRUE if arg0/arg1 are equal to the source arguments of a | |
618 | an EQ comparison feeding a BIT_AND_EXPR which feeds COND. | |
619 | ||
620 | Return FALSE otherwise. */ | |
621 | ||
622 | static bool | |
623 | operand_equal_for_value_replacement (const_tree arg0, const_tree arg1, | |
624 | enum tree_code *code, gimple cond) | |
625 | { | |
626 | gimple def; | |
627 | tree lhs = gimple_cond_lhs (cond); | |
628 | tree rhs = gimple_cond_rhs (cond); | |
629 | ||
630 | if ((operand_equal_for_phi_arg_p (arg0, lhs) | |
631 | && operand_equal_for_phi_arg_p (arg1, rhs)) | |
632 | || (operand_equal_for_phi_arg_p (arg1, lhs) | |
633 | && operand_equal_for_phi_arg_p (arg0, rhs))) | |
634 | return true; | |
635 | ||
636 | /* Now handle more complex case where we have an EQ comparison | |
637 | which feeds a BIT_AND_EXPR which feeds COND. | |
638 | ||
639 | First verify that COND is of the form SSA_NAME NE 0. */ | |
640 | if (*code != NE_EXPR || !integer_zerop (rhs) | |
641 | || TREE_CODE (lhs) != SSA_NAME) | |
642 | return false; | |
643 | ||
644 | /* Now ensure that SSA_NAME is set by a BIT_AND_EXPR. */ | |
645 | def = SSA_NAME_DEF_STMT (lhs); | |
646 | if (!is_gimple_assign (def) || gimple_assign_rhs_code (def) != BIT_AND_EXPR) | |
647 | return false; | |
648 | ||
649 | /* Now verify arg0/arg1 correspond to the source arguments of an | |
650 | EQ comparison feeding the BIT_AND_EXPR. */ | |
651 | ||
652 | tree tmp = gimple_assign_rhs1 (def); | |
653 | if (rhs_is_fed_for_value_replacement (arg0, arg1, code, tmp)) | |
654 | return true; | |
655 | ||
656 | tmp = gimple_assign_rhs2 (def); | |
657 | if (rhs_is_fed_for_value_replacement (arg0, arg1, code, tmp)) | |
658 | return true; | |
659 | ||
660 | return false; | |
661 | } | |
662 | ||
b6814ca0 | 663 | /* Returns true if ARG is a neutral element for operation CODE |
664 | on the RIGHT side. */ | |
665 | ||
666 | static bool | |
667 | neutral_element_p (tree_code code, tree arg, bool right) | |
668 | { | |
669 | switch (code) | |
670 | { | |
671 | case PLUS_EXPR: | |
672 | case BIT_IOR_EXPR: | |
673 | case BIT_XOR_EXPR: | |
674 | return integer_zerop (arg); | |
675 | ||
676 | case LROTATE_EXPR: | |
677 | case RROTATE_EXPR: | |
678 | case LSHIFT_EXPR: | |
679 | case RSHIFT_EXPR: | |
680 | case MINUS_EXPR: | |
681 | case POINTER_PLUS_EXPR: | |
682 | return right && integer_zerop (arg); | |
683 | ||
684 | case MULT_EXPR: | |
685 | return integer_onep (arg); | |
686 | ||
687 | case TRUNC_DIV_EXPR: | |
688 | case CEIL_DIV_EXPR: | |
689 | case FLOOR_DIV_EXPR: | |
690 | case ROUND_DIV_EXPR: | |
691 | case EXACT_DIV_EXPR: | |
692 | return right && integer_onep (arg); | |
693 | ||
694 | case BIT_AND_EXPR: | |
695 | return integer_all_onesp (arg); | |
696 | ||
697 | default: | |
698 | return false; | |
699 | } | |
700 | } | |
701 | ||
702 | /* Returns true if ARG is an absorbing element for operation CODE. */ | |
703 | ||
704 | static bool | |
705 | absorbing_element_p (tree_code code, tree arg) | |
706 | { | |
707 | switch (code) | |
708 | { | |
709 | case BIT_IOR_EXPR: | |
710 | return integer_all_onesp (arg); | |
711 | ||
712 | case MULT_EXPR: | |
713 | case BIT_AND_EXPR: | |
714 | return integer_zerop (arg); | |
715 | ||
716 | default: | |
717 | return false; | |
718 | } | |
719 | } | |
720 | ||
0beac6fc | 721 | /* The function value_replacement does the main work of doing the value |
fb9912ea | 722 | replacement. Return non-zero if the replacement is done. Otherwise return |
723 | 0. If we remove the middle basic block, return 2. | |
0beac6fc | 724 | BB is the basic block where the replacement is going to be done on. ARG0 |
dac49aa5 | 725 | is argument 0 from the PHI. Likewise for ARG1. */ |
0beac6fc | 726 | |
fb9912ea | 727 | static int |
33784d89 | 728 | value_replacement (basic_block cond_bb, basic_block middle_bb, |
75a70cf9 | 729 | edge e0, edge e1, gimple phi, |
33784d89 | 730 | tree arg0, tree arg1) |
0beac6fc | 731 | { |
17b9476e | 732 | gimple_stmt_iterator gsi; |
75a70cf9 | 733 | gimple cond; |
0beac6fc | 734 | edge true_edge, false_edge; |
75a70cf9 | 735 | enum tree_code code; |
fb9912ea | 736 | bool emtpy_or_with_defined_p = true; |
0beac6fc | 737 | |
738 | /* If the type says honor signed zeros we cannot do this | |
dac49aa5 | 739 | optimization. */ |
0beac6fc | 740 | if (HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (arg1)))) |
fb9912ea | 741 | return 0; |
0beac6fc | 742 | |
fb9912ea | 743 | /* If there is a statement in MIDDLE_BB that defines one of the PHI |
744 | arguments, then adjust arg0 or arg1. */ | |
b6814ca0 | 745 | gsi = gsi_start_nondebug_after_labels_bb (middle_bb); |
fb9912ea | 746 | while (!gsi_end_p (gsi)) |
17b9476e | 747 | { |
fb9912ea | 748 | gimple stmt = gsi_stmt (gsi); |
749 | tree lhs; | |
750 | gsi_next_nondebug (&gsi); | |
751 | if (!is_gimple_assign (stmt)) | |
17b9476e | 752 | { |
fb9912ea | 753 | emtpy_or_with_defined_p = false; |
754 | continue; | |
17b9476e | 755 | } |
fb9912ea | 756 | /* Now try to adjust arg0 or arg1 according to the computation |
757 | in the statement. */ | |
758 | lhs = gimple_assign_lhs (stmt); | |
759 | if (!(lhs == arg0 | |
760 | && jump_function_from_stmt (&arg0, stmt)) | |
761 | || (lhs == arg1 | |
762 | && jump_function_from_stmt (&arg1, stmt))) | |
763 | emtpy_or_with_defined_p = false; | |
17b9476e | 764 | } |
0beac6fc | 765 | |
75a70cf9 | 766 | cond = last_stmt (cond_bb); |
767 | code = gimple_cond_code (cond); | |
0beac6fc | 768 | |
769 | /* This transformation is only valid for equality comparisons. */ | |
75a70cf9 | 770 | if (code != NE_EXPR && code != EQ_EXPR) |
fb9912ea | 771 | return 0; |
0beac6fc | 772 | |
773 | /* We need to know which is the true edge and which is the false | |
774 | edge so that we know if have abs or negative abs. */ | |
33784d89 | 775 | extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge); |
0beac6fc | 776 | |
777 | /* At this point we know we have a COND_EXPR with two successors. | |
778 | One successor is BB, the other successor is an empty block which | |
779 | falls through into BB. | |
780 | ||
781 | The condition for the COND_EXPR is known to be NE_EXPR or EQ_EXPR. | |
782 | ||
783 | There is a single PHI node at the join point (BB) with two arguments. | |
784 | ||
785 | We now need to verify that the two arguments in the PHI node match | |
786 | the two arguments to the equality comparison. */ | |
20e5647c | 787 | |
f32420fb | 788 | if (operand_equal_for_value_replacement (arg0, arg1, &code, cond)) |
0beac6fc | 789 | { |
790 | edge e; | |
791 | tree arg; | |
792 | ||
50737d20 | 793 | /* For NE_EXPR, we want to build an assignment result = arg where |
794 | arg is the PHI argument associated with the true edge. For | |
795 | EQ_EXPR we want the PHI argument associated with the false edge. */ | |
75a70cf9 | 796 | e = (code == NE_EXPR ? true_edge : false_edge); |
50737d20 | 797 | |
798 | /* Unfortunately, E may not reach BB (it may instead have gone to | |
799 | OTHER_BLOCK). If that is the case, then we want the single outgoing | |
800 | edge from OTHER_BLOCK which reaches BB and represents the desired | |
801 | path from COND_BLOCK. */ | |
33784d89 | 802 | if (e->dest == middle_bb) |
ea091dfd | 803 | e = single_succ_edge (e->dest); |
50737d20 | 804 | |
805 | /* Now we know the incoming edge to BB that has the argument for the | |
806 | RHS of our new assignment statement. */ | |
33784d89 | 807 | if (e0 == e) |
0beac6fc | 808 | arg = arg0; |
809 | else | |
810 | arg = arg1; | |
811 | ||
fb9912ea | 812 | /* If the middle basic block was empty or is defining the |
c3597b05 | 813 | PHI arguments and this is a single phi where the args are different |
814 | for the edges e0 and e1 then we can remove the middle basic block. */ | |
fb9912ea | 815 | if (emtpy_or_with_defined_p |
c3597b05 | 816 | && single_non_singleton_phi_for_edges (phi_nodes (gimple_bb (phi)), |
817 | e0, e1)) | |
fb9912ea | 818 | { |
819 | replace_phi_edge_with_variable (cond_bb, e1, phi, arg); | |
820 | /* Note that we optimized this PHI. */ | |
821 | return 2; | |
822 | } | |
823 | else | |
824 | { | |
825 | /* Replace the PHI arguments with arg. */ | |
826 | SET_PHI_ARG_DEF (phi, e0->dest_idx, arg); | |
827 | SET_PHI_ARG_DEF (phi, e1->dest_idx, arg); | |
828 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
829 | { | |
830 | fprintf (dump_file, "PHI "); | |
831 | print_generic_expr (dump_file, gimple_phi_result (phi), 0); | |
c3597b05 | 832 | fprintf (dump_file, " reduced for COND_EXPR in block %d to ", |
833 | cond_bb->index); | |
fb9912ea | 834 | print_generic_expr (dump_file, arg, 0); |
835 | fprintf (dump_file, ".\n"); | |
836 | } | |
837 | return 1; | |
838 | } | |
0beac6fc | 839 | |
0beac6fc | 840 | } |
b6814ca0 | 841 | |
842 | /* Now optimize (x != 0) ? x + y : y to just y. | |
843 | The following condition is too restrictive, there can easily be another | |
844 | stmt in middle_bb, for instance a CONVERT_EXPR for the second argument. */ | |
845 | gimple assign = last_and_only_stmt (middle_bb); | |
846 | if (!assign || gimple_code (assign) != GIMPLE_ASSIGN | |
847 | || gimple_assign_rhs_class (assign) != GIMPLE_BINARY_RHS | |
848 | || (!INTEGRAL_TYPE_P (TREE_TYPE (arg0)) | |
849 | && !POINTER_TYPE_P (TREE_TYPE (arg0)))) | |
850 | return 0; | |
851 | ||
6c96fe34 | 852 | /* Punt if there are (degenerate) PHIs in middle_bb, there should not be. */ |
853 | if (!gimple_seq_empty_p (phi_nodes (middle_bb))) | |
854 | return 0; | |
855 | ||
43fbec4a | 856 | /* Only transform if it removes the condition. */ |
857 | if (!single_non_singleton_phi_for_edges (phi_nodes (gimple_bb (phi)), e0, e1)) | |
858 | return 0; | |
859 | ||
b6814ca0 | 860 | /* Size-wise, this is always profitable. */ |
861 | if (optimize_bb_for_speed_p (cond_bb) | |
862 | /* The special case is useless if it has a low probability. */ | |
863 | && profile_status_for_fn (cfun) != PROFILE_ABSENT | |
864 | && EDGE_PRED (middle_bb, 0)->probability < PROB_EVEN | |
865 | /* If assign is cheap, there is no point avoiding it. */ | |
866 | && estimate_num_insns (assign, &eni_time_weights) | |
867 | >= 3 * estimate_num_insns (cond, &eni_time_weights)) | |
868 | return 0; | |
869 | ||
870 | tree lhs = gimple_assign_lhs (assign); | |
871 | tree rhs1 = gimple_assign_rhs1 (assign); | |
872 | tree rhs2 = gimple_assign_rhs2 (assign); | |
873 | enum tree_code code_def = gimple_assign_rhs_code (assign); | |
874 | tree cond_lhs = gimple_cond_lhs (cond); | |
875 | tree cond_rhs = gimple_cond_rhs (cond); | |
876 | ||
877 | if (((code == NE_EXPR && e1 == false_edge) | |
878 | || (code == EQ_EXPR && e1 == true_edge)) | |
879 | && arg0 == lhs | |
880 | && ((arg1 == rhs1 | |
881 | && operand_equal_for_phi_arg_p (rhs2, cond_lhs) | |
882 | && neutral_element_p (code_def, cond_rhs, true)) | |
883 | || (arg1 == rhs2 | |
884 | && operand_equal_for_phi_arg_p (rhs1, cond_lhs) | |
885 | && neutral_element_p (code_def, cond_rhs, false)) | |
886 | || (operand_equal_for_phi_arg_p (arg1, cond_rhs) | |
887 | && (operand_equal_for_phi_arg_p (rhs2, cond_lhs) | |
888 | || operand_equal_for_phi_arg_p (rhs1, cond_lhs)) | |
889 | && absorbing_element_p (code_def, cond_rhs)))) | |
890 | { | |
891 | gsi = gsi_for_stmt (cond); | |
892 | gimple_stmt_iterator gsi_from = gsi_for_stmt (assign); | |
893 | gsi_move_before (&gsi_from, &gsi); | |
894 | replace_phi_edge_with_variable (cond_bb, e1, phi, lhs); | |
895 | return 2; | |
896 | } | |
897 | ||
fb9912ea | 898 | return 0; |
0beac6fc | 899 | } |
900 | ||
194899bf | 901 | /* The function minmax_replacement does the main work of doing the minmax |
902 | replacement. Return true if the replacement is done. Otherwise return | |
903 | false. | |
904 | BB is the basic block where the replacement is going to be done on. ARG0 | |
905 | is argument 0 from the PHI. Likewise for ARG1. */ | |
906 | ||
907 | static bool | |
908 | minmax_replacement (basic_block cond_bb, basic_block middle_bb, | |
75a70cf9 | 909 | edge e0, edge e1, gimple phi, |
194899bf | 910 | tree arg0, tree arg1) |
911 | { | |
912 | tree result, type; | |
75a70cf9 | 913 | gimple cond, new_stmt; |
194899bf | 914 | edge true_edge, false_edge; |
915 | enum tree_code cmp, minmax, ass_code; | |
916 | tree smaller, larger, arg_true, arg_false; | |
75a70cf9 | 917 | gimple_stmt_iterator gsi, gsi_from; |
194899bf | 918 | |
919 | type = TREE_TYPE (PHI_RESULT (phi)); | |
920 | ||
921 | /* The optimization may be unsafe due to NaNs. */ | |
922 | if (HONOR_NANS (TYPE_MODE (type))) | |
923 | return false; | |
924 | ||
75a70cf9 | 925 | cond = last_stmt (cond_bb); |
926 | cmp = gimple_cond_code (cond); | |
194899bf | 927 | |
928 | /* This transformation is only valid for order comparisons. Record which | |
929 | operand is smaller/larger if the result of the comparison is true. */ | |
930 | if (cmp == LT_EXPR || cmp == LE_EXPR) | |
931 | { | |
75a70cf9 | 932 | smaller = gimple_cond_lhs (cond); |
933 | larger = gimple_cond_rhs (cond); | |
194899bf | 934 | } |
935 | else if (cmp == GT_EXPR || cmp == GE_EXPR) | |
936 | { | |
75a70cf9 | 937 | smaller = gimple_cond_rhs (cond); |
938 | larger = gimple_cond_lhs (cond); | |
194899bf | 939 | } |
940 | else | |
941 | return false; | |
942 | ||
943 | /* We need to know which is the true edge and which is the false | |
944 | edge so that we know if have abs or negative abs. */ | |
945 | extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge); | |
946 | ||
947 | /* Forward the edges over the middle basic block. */ | |
948 | if (true_edge->dest == middle_bb) | |
949 | true_edge = EDGE_SUCC (true_edge->dest, 0); | |
950 | if (false_edge->dest == middle_bb) | |
951 | false_edge = EDGE_SUCC (false_edge->dest, 0); | |
952 | ||
953 | if (true_edge == e0) | |
954 | { | |
955 | gcc_assert (false_edge == e1); | |
956 | arg_true = arg0; | |
957 | arg_false = arg1; | |
958 | } | |
959 | else | |
960 | { | |
961 | gcc_assert (false_edge == e0); | |
962 | gcc_assert (true_edge == e1); | |
963 | arg_true = arg1; | |
964 | arg_false = arg0; | |
965 | } | |
966 | ||
967 | if (empty_block_p (middle_bb)) | |
968 | { | |
969 | if (operand_equal_for_phi_arg_p (arg_true, smaller) | |
970 | && operand_equal_for_phi_arg_p (arg_false, larger)) | |
971 | { | |
972 | /* Case | |
48e1416a | 973 | |
194899bf | 974 | if (smaller < larger) |
975 | rslt = smaller; | |
976 | else | |
977 | rslt = larger; */ | |
978 | minmax = MIN_EXPR; | |
979 | } | |
980 | else if (operand_equal_for_phi_arg_p (arg_false, smaller) | |
981 | && operand_equal_for_phi_arg_p (arg_true, larger)) | |
982 | minmax = MAX_EXPR; | |
983 | else | |
984 | return false; | |
985 | } | |
986 | else | |
987 | { | |
988 | /* Recognize the following case, assuming d <= u: | |
989 | ||
990 | if (a <= u) | |
991 | b = MAX (a, d); | |
992 | x = PHI <b, u> | |
993 | ||
994 | This is equivalent to | |
995 | ||
996 | b = MAX (a, d); | |
997 | x = MIN (b, u); */ | |
998 | ||
75a70cf9 | 999 | gimple assign = last_and_only_stmt (middle_bb); |
1000 | tree lhs, op0, op1, bound; | |
194899bf | 1001 | |
1002 | if (!assign | |
75a70cf9 | 1003 | || gimple_code (assign) != GIMPLE_ASSIGN) |
194899bf | 1004 | return false; |
1005 | ||
75a70cf9 | 1006 | lhs = gimple_assign_lhs (assign); |
1007 | ass_code = gimple_assign_rhs_code (assign); | |
194899bf | 1008 | if (ass_code != MAX_EXPR && ass_code != MIN_EXPR) |
1009 | return false; | |
75a70cf9 | 1010 | op0 = gimple_assign_rhs1 (assign); |
1011 | op1 = gimple_assign_rhs2 (assign); | |
194899bf | 1012 | |
1013 | if (true_edge->src == middle_bb) | |
1014 | { | |
1015 | /* We got here if the condition is true, i.e., SMALLER < LARGER. */ | |
1016 | if (!operand_equal_for_phi_arg_p (lhs, arg_true)) | |
1017 | return false; | |
1018 | ||
1019 | if (operand_equal_for_phi_arg_p (arg_false, larger)) | |
1020 | { | |
1021 | /* Case | |
1022 | ||
1023 | if (smaller < larger) | |
1024 | { | |
1025 | r' = MAX_EXPR (smaller, bound) | |
1026 | } | |
1027 | r = PHI <r', larger> --> to be turned to MIN_EXPR. */ | |
1028 | if (ass_code != MAX_EXPR) | |
1029 | return false; | |
1030 | ||
1031 | minmax = MIN_EXPR; | |
1032 | if (operand_equal_for_phi_arg_p (op0, smaller)) | |
1033 | bound = op1; | |
1034 | else if (operand_equal_for_phi_arg_p (op1, smaller)) | |
1035 | bound = op0; | |
1036 | else | |
1037 | return false; | |
1038 | ||
1039 | /* We need BOUND <= LARGER. */ | |
49d00087 | 1040 | if (!integer_nonzerop (fold_build2 (LE_EXPR, boolean_type_node, |
1041 | bound, larger))) | |
194899bf | 1042 | return false; |
1043 | } | |
1044 | else if (operand_equal_for_phi_arg_p (arg_false, smaller)) | |
1045 | { | |
1046 | /* Case | |
1047 | ||
1048 | if (smaller < larger) | |
1049 | { | |
1050 | r' = MIN_EXPR (larger, bound) | |
1051 | } | |
1052 | r = PHI <r', smaller> --> to be turned to MAX_EXPR. */ | |
1053 | if (ass_code != MIN_EXPR) | |
1054 | return false; | |
1055 | ||
1056 | minmax = MAX_EXPR; | |
1057 | if (operand_equal_for_phi_arg_p (op0, larger)) | |
1058 | bound = op1; | |
1059 | else if (operand_equal_for_phi_arg_p (op1, larger)) | |
1060 | bound = op0; | |
1061 | else | |
1062 | return false; | |
1063 | ||
1064 | /* We need BOUND >= SMALLER. */ | |
49d00087 | 1065 | if (!integer_nonzerop (fold_build2 (GE_EXPR, boolean_type_node, |
1066 | bound, smaller))) | |
194899bf | 1067 | return false; |
1068 | } | |
1069 | else | |
1070 | return false; | |
1071 | } | |
1072 | else | |
1073 | { | |
1074 | /* We got here if the condition is false, i.e., SMALLER > LARGER. */ | |
1075 | if (!operand_equal_for_phi_arg_p (lhs, arg_false)) | |
1076 | return false; | |
1077 | ||
1078 | if (operand_equal_for_phi_arg_p (arg_true, larger)) | |
1079 | { | |
1080 | /* Case | |
1081 | ||
1082 | if (smaller > larger) | |
1083 | { | |
1084 | r' = MIN_EXPR (smaller, bound) | |
1085 | } | |
1086 | r = PHI <r', larger> --> to be turned to MAX_EXPR. */ | |
1087 | if (ass_code != MIN_EXPR) | |
1088 | return false; | |
1089 | ||
1090 | minmax = MAX_EXPR; | |
1091 | if (operand_equal_for_phi_arg_p (op0, smaller)) | |
1092 | bound = op1; | |
1093 | else if (operand_equal_for_phi_arg_p (op1, smaller)) | |
1094 | bound = op0; | |
1095 | else | |
1096 | return false; | |
1097 | ||
1098 | /* We need BOUND >= LARGER. */ | |
49d00087 | 1099 | if (!integer_nonzerop (fold_build2 (GE_EXPR, boolean_type_node, |
1100 | bound, larger))) | |
194899bf | 1101 | return false; |
1102 | } | |
1103 | else if (operand_equal_for_phi_arg_p (arg_true, smaller)) | |
1104 | { | |
1105 | /* Case | |
1106 | ||
1107 | if (smaller > larger) | |
1108 | { | |
1109 | r' = MAX_EXPR (larger, bound) | |
1110 | } | |
1111 | r = PHI <r', smaller> --> to be turned to MIN_EXPR. */ | |
1112 | if (ass_code != MAX_EXPR) | |
1113 | return false; | |
1114 | ||
1115 | minmax = MIN_EXPR; | |
1116 | if (operand_equal_for_phi_arg_p (op0, larger)) | |
1117 | bound = op1; | |
1118 | else if (operand_equal_for_phi_arg_p (op1, larger)) | |
1119 | bound = op0; | |
1120 | else | |
1121 | return false; | |
1122 | ||
1123 | /* We need BOUND <= SMALLER. */ | |
49d00087 | 1124 | if (!integer_nonzerop (fold_build2 (LE_EXPR, boolean_type_node, |
1125 | bound, smaller))) | |
194899bf | 1126 | return false; |
1127 | } | |
1128 | else | |
1129 | return false; | |
1130 | } | |
1131 | ||
1132 | /* Move the statement from the middle block. */ | |
75a70cf9 | 1133 | gsi = gsi_last_bb (cond_bb); |
445a6ba5 | 1134 | gsi_from = gsi_last_nondebug_bb (middle_bb); |
75a70cf9 | 1135 | gsi_move_before (&gsi_from, &gsi); |
194899bf | 1136 | } |
1137 | ||
1138 | /* Emit the statement to compute min/max. */ | |
1139 | result = duplicate_ssa_name (PHI_RESULT (phi), NULL); | |
75a70cf9 | 1140 | new_stmt = gimple_build_assign_with_ops (minmax, result, arg0, arg1); |
1141 | gsi = gsi_last_bb (cond_bb); | |
1142 | gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT); | |
194899bf | 1143 | |
a4844041 | 1144 | replace_phi_edge_with_variable (cond_bb, e1, phi, result); |
194899bf | 1145 | return true; |
1146 | } | |
1147 | ||
70512b93 | 1148 | /* The function absolute_replacement does the main work of doing the absolute |
1149 | replacement. Return true if the replacement is done. Otherwise return | |
1150 | false. | |
1151 | bb is the basic block where the replacement is going to be done on. arg0 | |
f7f07c95 | 1152 | is argument 0 from the phi. Likewise for arg1. */ |
33784d89 | 1153 | |
70512b93 | 1154 | static bool |
33784d89 | 1155 | abs_replacement (basic_block cond_bb, basic_block middle_bb, |
a4844041 | 1156 | edge e0 ATTRIBUTE_UNUSED, edge e1, |
75a70cf9 | 1157 | gimple phi, tree arg0, tree arg1) |
70512b93 | 1158 | { |
1159 | tree result; | |
75a70cf9 | 1160 | gimple new_stmt, cond; |
1161 | gimple_stmt_iterator gsi; | |
70512b93 | 1162 | edge true_edge, false_edge; |
75a70cf9 | 1163 | gimple assign; |
70512b93 | 1164 | edge e; |
194899bf | 1165 | tree rhs, lhs; |
70512b93 | 1166 | bool negate; |
1167 | enum tree_code cond_code; | |
1168 | ||
1169 | /* If the type says honor signed zeros we cannot do this | |
dac49aa5 | 1170 | optimization. */ |
70512b93 | 1171 | if (HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (arg1)))) |
1172 | return false; | |
1173 | ||
70512b93 | 1174 | /* OTHER_BLOCK must have only one executable statement which must have the |
1175 | form arg0 = -arg1 or arg1 = -arg0. */ | |
70512b93 | 1176 | |
194899bf | 1177 | assign = last_and_only_stmt (middle_bb); |
70512b93 | 1178 | /* If we did not find the proper negation assignment, then we can not |
1179 | optimize. */ | |
1180 | if (assign == NULL) | |
1181 | return false; | |
48e1416a | 1182 | |
194899bf | 1183 | /* If we got here, then we have found the only executable statement |
1184 | in OTHER_BLOCK. If it is anything other than arg = -arg1 or | |
1185 | arg1 = -arg0, then we can not optimize. */ | |
75a70cf9 | 1186 | if (gimple_code (assign) != GIMPLE_ASSIGN) |
194899bf | 1187 | return false; |
1188 | ||
75a70cf9 | 1189 | lhs = gimple_assign_lhs (assign); |
194899bf | 1190 | |
75a70cf9 | 1191 | if (gimple_assign_rhs_code (assign) != NEGATE_EXPR) |
194899bf | 1192 | return false; |
1193 | ||
75a70cf9 | 1194 | rhs = gimple_assign_rhs1 (assign); |
48e1416a | 1195 | |
194899bf | 1196 | /* The assignment has to be arg0 = -arg1 or arg1 = -arg0. */ |
1197 | if (!(lhs == arg0 && rhs == arg1) | |
1198 | && !(lhs == arg1 && rhs == arg0)) | |
1199 | return false; | |
70512b93 | 1200 | |
75a70cf9 | 1201 | cond = last_stmt (cond_bb); |
70512b93 | 1202 | result = PHI_RESULT (phi); |
1203 | ||
1204 | /* Only relationals comparing arg[01] against zero are interesting. */ | |
75a70cf9 | 1205 | cond_code = gimple_cond_code (cond); |
70512b93 | 1206 | if (cond_code != GT_EXPR && cond_code != GE_EXPR |
1207 | && cond_code != LT_EXPR && cond_code != LE_EXPR) | |
1208 | return false; | |
1209 | ||
dac49aa5 | 1210 | /* Make sure the conditional is arg[01] OP y. */ |
75a70cf9 | 1211 | if (gimple_cond_lhs (cond) != rhs) |
70512b93 | 1212 | return false; |
1213 | ||
75a70cf9 | 1214 | if (FLOAT_TYPE_P (TREE_TYPE (gimple_cond_rhs (cond))) |
1215 | ? real_zerop (gimple_cond_rhs (cond)) | |
1216 | : integer_zerop (gimple_cond_rhs (cond))) | |
70512b93 | 1217 | ; |
1218 | else | |
1219 | return false; | |
1220 | ||
1221 | /* We need to know which is the true edge and which is the false | |
1222 | edge so that we know if have abs or negative abs. */ | |
33784d89 | 1223 | extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge); |
70512b93 | 1224 | |
1225 | /* For GT_EXPR/GE_EXPR, if the true edge goes to OTHER_BLOCK, then we | |
1226 | will need to negate the result. Similarly for LT_EXPR/LE_EXPR if | |
1227 | the false edge goes to OTHER_BLOCK. */ | |
1228 | if (cond_code == GT_EXPR || cond_code == GE_EXPR) | |
1229 | e = true_edge; | |
1230 | else | |
1231 | e = false_edge; | |
20e5647c | 1232 | |
33784d89 | 1233 | if (e->dest == middle_bb) |
70512b93 | 1234 | negate = true; |
1235 | else | |
1236 | negate = false; | |
20e5647c | 1237 | |
33784d89 | 1238 | result = duplicate_ssa_name (result, NULL); |
20e5647c | 1239 | |
70512b93 | 1240 | if (negate) |
03d37e4e | 1241 | lhs = make_ssa_name (TREE_TYPE (result), NULL); |
70512b93 | 1242 | else |
1243 | lhs = result; | |
1244 | ||
dac49aa5 | 1245 | /* Build the modify expression with abs expression. */ |
75a70cf9 | 1246 | new_stmt = gimple_build_assign_with_ops (ABS_EXPR, lhs, rhs, NULL); |
70512b93 | 1247 | |
75a70cf9 | 1248 | gsi = gsi_last_bb (cond_bb); |
1249 | gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT); | |
70512b93 | 1250 | |
1251 | if (negate) | |
1252 | { | |
75a70cf9 | 1253 | /* Get the right GSI. We want to insert after the recently |
70512b93 | 1254 | added ABS_EXPR statement (which we know is the first statement |
1255 | in the block. */ | |
75a70cf9 | 1256 | new_stmt = gimple_build_assign_with_ops (NEGATE_EXPR, result, lhs, NULL); |
70512b93 | 1257 | |
75a70cf9 | 1258 | gsi_insert_after (&gsi, new_stmt, GSI_NEW_STMT); |
70512b93 | 1259 | } |
20e5647c | 1260 | |
a4844041 | 1261 | replace_phi_edge_with_variable (cond_bb, e1, phi, result); |
70512b93 | 1262 | |
1263 | /* Note that we optimized this PHI. */ | |
1264 | return true; | |
1265 | } | |
1266 | ||
88747429 | 1267 | /* The function neg_replacement replaces conditional negation with |
1268 | equivalent straight line code. Returns TRUE if replacement is done, | |
1269 | otherwise returns FALSE. | |
1270 | ||
1271 | COND_BB branches around negation occuring in MIDDLE_BB. | |
1272 | ||
1273 | E0 and E1 are edges out of COND_BB. E0 reaches MIDDLE_BB and | |
1274 | E1 reaches the other successor which should contain PHI with | |
1275 | arguments ARG0 and ARG1. | |
1276 | ||
1277 | Assuming negation is to occur when the condition is true, | |
1278 | then the non-branching sequence is: | |
1279 | ||
1280 | result = (rhs ^ -cond) + cond | |
1281 | ||
1282 | Inverting the condition or its result gives us negation | |
1283 | when the original condition is false. */ | |
1284 | ||
1285 | static bool | |
1286 | neg_replacement (basic_block cond_bb, basic_block middle_bb, | |
1287 | edge e0 ATTRIBUTE_UNUSED, edge e1, | |
1288 | gimple phi, tree arg0, tree arg1) | |
1289 | { | |
1290 | gimple new_stmt, cond; | |
1291 | gimple_stmt_iterator gsi; | |
1292 | gimple assign; | |
1293 | edge true_edge, false_edge; | |
1294 | tree rhs, lhs; | |
1295 | enum tree_code cond_code; | |
1296 | bool invert = false; | |
1297 | ||
1298 | /* This transformation performs logical operations on the | |
1299 | incoming arguments. So force them to be integral types. */ | |
1300 | if (!INTEGRAL_TYPE_P (TREE_TYPE (arg0))) | |
1301 | return false; | |
1302 | ||
1303 | /* OTHER_BLOCK must have only one executable statement which must have the | |
1304 | form arg0 = -arg1 or arg1 = -arg0. */ | |
1305 | ||
1306 | assign = last_and_only_stmt (middle_bb); | |
1307 | /* If we did not find the proper negation assignment, then we can not | |
1308 | optimize. */ | |
1309 | if (assign == NULL) | |
1310 | return false; | |
1311 | ||
1312 | /* If we got here, then we have found the only executable statement | |
1313 | in OTHER_BLOCK. If it is anything other than arg0 = -arg1 or | |
1314 | arg1 = -arg0, then we can not optimize. */ | |
1315 | if (gimple_code (assign) != GIMPLE_ASSIGN) | |
1316 | return false; | |
1317 | ||
1318 | lhs = gimple_assign_lhs (assign); | |
1319 | ||
1320 | if (gimple_assign_rhs_code (assign) != NEGATE_EXPR) | |
1321 | return false; | |
1322 | ||
1323 | rhs = gimple_assign_rhs1 (assign); | |
1324 | ||
1325 | /* The assignment has to be arg0 = -arg1 or arg1 = -arg0. */ | |
1326 | if (!(lhs == arg0 && rhs == arg1) | |
1327 | && !(lhs == arg1 && rhs == arg0)) | |
1328 | return false; | |
1329 | ||
1330 | /* The basic sequence assumes we negate when the condition is true. | |
1331 | If we need the opposite, then we will either need to invert the | |
1332 | condition or its result. */ | |
1333 | extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge); | |
1334 | invert = false_edge->dest == middle_bb; | |
1335 | ||
1336 | /* Unlike abs_replacement, we can handle arbitrary conditionals here. */ | |
1337 | cond = last_stmt (cond_bb); | |
1338 | cond_code = gimple_cond_code (cond); | |
1339 | ||
1340 | /* If inversion is needed, first try to invert the test since | |
1341 | that's cheapest. */ | |
1342 | if (invert) | |
1343 | { | |
1344 | bool honor_nans | |
1345 | = HONOR_NANS (TYPE_MODE (TREE_TYPE (gimple_cond_lhs (cond)))); | |
1346 | enum tree_code new_code = invert_tree_comparison (cond_code, honor_nans); | |
1347 | ||
1348 | /* If invert_tree_comparison was successful, then use its return | |
1349 | value as the new code and note that inversion is no longer | |
1350 | needed. */ | |
1351 | if (new_code != ERROR_MARK) | |
1352 | { | |
1353 | cond_code = new_code; | |
1354 | invert = false; | |
1355 | } | |
1356 | } | |
1357 | ||
1358 | tree cond_val = make_ssa_name (boolean_type_node, NULL); | |
1359 | new_stmt = gimple_build_assign_with_ops (cond_code, cond_val, | |
1360 | gimple_cond_lhs (cond), | |
1361 | gimple_cond_rhs (cond)); | |
1362 | gsi = gsi_last_bb (cond_bb); | |
1363 | gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT); | |
1364 | ||
1365 | /* If we still need inversion, then invert the result of the | |
1366 | condition. */ | |
1367 | if (invert) | |
1368 | { | |
1369 | tree tmp = make_ssa_name (boolean_type_node, NULL); | |
1370 | new_stmt = gimple_build_assign_with_ops (BIT_XOR_EXPR, tmp, | |
1371 | cond_val, boolean_true_node); | |
1372 | gsi_insert_after (&gsi, new_stmt, GSI_NEW_STMT); | |
1373 | cond_val = tmp; | |
1374 | } | |
1375 | ||
1376 | /* Get the condition in the right type so that we can perform | |
1377 | logical and arithmetic operations on it. */ | |
1378 | tree cond_val_converted = make_ssa_name (TREE_TYPE (rhs), NULL); | |
1379 | new_stmt = gimple_build_assign_with_ops (NOP_EXPR, cond_val_converted, | |
1380 | cond_val, NULL_TREE); | |
1381 | gsi_insert_after (&gsi, new_stmt, GSI_NEW_STMT); | |
1382 | ||
1383 | tree neg_cond_val_converted = make_ssa_name (TREE_TYPE (rhs), NULL); | |
1384 | new_stmt = gimple_build_assign_with_ops (NEGATE_EXPR, neg_cond_val_converted, | |
1385 | cond_val_converted, NULL_TREE); | |
1386 | gsi_insert_after (&gsi, new_stmt, GSI_NEW_STMT); | |
1387 | ||
1388 | tree tmp = make_ssa_name (TREE_TYPE (rhs), NULL); | |
1389 | new_stmt = gimple_build_assign_with_ops (BIT_XOR_EXPR, tmp, | |
1390 | rhs, neg_cond_val_converted); | |
1391 | gsi_insert_after (&gsi, new_stmt, GSI_NEW_STMT); | |
1392 | ||
1393 | tree new_lhs = make_ssa_name (TREE_TYPE (rhs), NULL); | |
1394 | new_stmt = gimple_build_assign_with_ops (PLUS_EXPR, new_lhs, | |
1395 | tmp, cond_val_converted); | |
1396 | gsi_insert_after (&gsi, new_stmt, GSI_NEW_STMT); | |
1397 | ||
1398 | replace_phi_edge_with_variable (cond_bb, e1, phi, new_lhs); | |
1399 | ||
1400 | /* Note that we optimized this PHI. */ | |
1401 | return true; | |
1402 | } | |
1403 | ||
e6d0e152 | 1404 | /* Auxiliary functions to determine the set of memory accesses which |
1405 | can't trap because they are preceded by accesses to the same memory | |
182cf5a9 | 1406 | portion. We do that for MEM_REFs, so we only need to track |
e6d0e152 | 1407 | the SSA_NAME of the pointer indirectly referenced. The algorithm |
1408 | simply is a walk over all instructions in dominator order. When | |
182cf5a9 | 1409 | we see an MEM_REF we determine if we've already seen a same |
e6d0e152 | 1410 | ref anywhere up to the root of the dominator tree. If we do the |
af4f74fa | 1411 | current access can't trap. If we don't see any dominating access |
e6d0e152 | 1412 | the current access might trap, but might also make later accesses |
af4f74fa | 1413 | non-trapping, so we remember it. We need to be careful with loads |
1414 | or stores, for instance a load might not trap, while a store would, | |
1415 | so if we see a dominating read access this doesn't mean that a later | |
1416 | write access would not trap. Hence we also need to differentiate the | |
1417 | type of access(es) seen. | |
1418 | ||
1419 | ??? We currently are very conservative and assume that a load might | |
1420 | trap even if a store doesn't (write-only memory). This probably is | |
1421 | overly conservative. */ | |
e6d0e152 | 1422 | |
182cf5a9 | 1423 | /* A hash-table of SSA_NAMEs, and in which basic block an MEM_REF |
e6d0e152 | 1424 | through it was seen, which would constitute a no-trap region for |
1425 | same accesses. */ | |
1426 | struct name_to_bb | |
1427 | { | |
963aee26 | 1428 | unsigned int ssa_name_ver; |
42540642 | 1429 | unsigned int phase; |
963aee26 | 1430 | bool store; |
1431 | HOST_WIDE_INT offset, size; | |
e6d0e152 | 1432 | basic_block bb; |
1433 | }; | |
1434 | ||
d9dd21a8 | 1435 | /* Hashtable helpers. */ |
1436 | ||
1437 | struct ssa_names_hasher : typed_free_remove <name_to_bb> | |
1438 | { | |
1439 | typedef name_to_bb value_type; | |
1440 | typedef name_to_bb compare_type; | |
1441 | static inline hashval_t hash (const value_type *); | |
1442 | static inline bool equal (const value_type *, const compare_type *); | |
1443 | }; | |
e6d0e152 | 1444 | |
42540642 | 1445 | /* Used for quick clearing of the hash-table when we see calls. |
1446 | Hash entries with phase < nt_call_phase are invalid. */ | |
1447 | static unsigned int nt_call_phase; | |
1448 | ||
963aee26 | 1449 | /* The hash function. */ |
d9dd21a8 | 1450 | |
1451 | inline hashval_t | |
1452 | ssa_names_hasher::hash (const value_type *n) | |
e6d0e152 | 1453 | { |
963aee26 | 1454 | return n->ssa_name_ver ^ (((hashval_t) n->store) << 31) |
1455 | ^ (n->offset << 6) ^ (n->size << 3); | |
e6d0e152 | 1456 | } |
1457 | ||
963aee26 | 1458 | /* The equality function of *P1 and *P2. */ |
e6d0e152 | 1459 | |
d9dd21a8 | 1460 | inline bool |
1461 | ssa_names_hasher::equal (const value_type *n1, const compare_type *n2) | |
1462 | { | |
963aee26 | 1463 | return n1->ssa_name_ver == n2->ssa_name_ver |
1464 | && n1->store == n2->store | |
1465 | && n1->offset == n2->offset | |
1466 | && n1->size == n2->size; | |
e6d0e152 | 1467 | } |
1468 | ||
c1f445d2 | 1469 | class nontrapping_dom_walker : public dom_walker |
1470 | { | |
1471 | public: | |
1472 | nontrapping_dom_walker (cdi_direction direction, pointer_set_t *ps) | |
1473 | : dom_walker (direction), m_nontrapping (ps), m_seen_ssa_names (128) {} | |
1474 | ||
1475 | virtual void before_dom_children (basic_block); | |
1476 | virtual void after_dom_children (basic_block); | |
1477 | ||
1478 | private: | |
1479 | ||
1480 | /* We see the expression EXP in basic block BB. If it's an interesting | |
1481 | expression (an MEM_REF through an SSA_NAME) possibly insert the | |
1482 | expression into the set NONTRAP or the hash table of seen expressions. | |
1483 | STORE is true if this expression is on the LHS, otherwise it's on | |
1484 | the RHS. */ | |
1485 | void add_or_mark_expr (basic_block, tree, bool); | |
1486 | ||
1487 | pointer_set_t *m_nontrapping; | |
1488 | ||
1489 | /* The hash table for remembering what we've seen. */ | |
1490 | hash_table<ssa_names_hasher> m_seen_ssa_names; | |
1491 | }; | |
1492 | ||
1493 | /* Called by walk_dominator_tree, when entering the block BB. */ | |
1494 | void | |
1495 | nontrapping_dom_walker::before_dom_children (basic_block bb) | |
1496 | { | |
1497 | edge e; | |
1498 | edge_iterator ei; | |
1499 | gimple_stmt_iterator gsi; | |
1500 | ||
1501 | /* If we haven't seen all our predecessors, clear the hash-table. */ | |
1502 | FOR_EACH_EDGE (e, ei, bb->preds) | |
1503 | if ((((size_t)e->src->aux) & 2) == 0) | |
1504 | { | |
1505 | nt_call_phase++; | |
1506 | break; | |
1507 | } | |
1508 | ||
1509 | /* Mark this BB as being on the path to dominator root and as visited. */ | |
1510 | bb->aux = (void*)(1 | 2); | |
1511 | ||
1512 | /* And walk the statements in order. */ | |
1513 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
1514 | { | |
1515 | gimple stmt = gsi_stmt (gsi); | |
1516 | ||
1517 | if (is_gimple_call (stmt) && !nonfreeing_call_p (stmt)) | |
1518 | nt_call_phase++; | |
1519 | else if (gimple_assign_single_p (stmt) && !gimple_has_volatile_ops (stmt)) | |
1520 | { | |
1521 | add_or_mark_expr (bb, gimple_assign_lhs (stmt), true); | |
1522 | add_or_mark_expr (bb, gimple_assign_rhs1 (stmt), false); | |
1523 | } | |
1524 | } | |
1525 | } | |
1526 | ||
1527 | /* Called by walk_dominator_tree, when basic block BB is exited. */ | |
1528 | void | |
1529 | nontrapping_dom_walker::after_dom_children (basic_block bb) | |
1530 | { | |
1531 | /* This BB isn't on the path to dominator root anymore. */ | |
1532 | bb->aux = (void*)2; | |
1533 | } | |
d9dd21a8 | 1534 | |
f0b5f617 | 1535 | /* We see the expression EXP in basic block BB. If it's an interesting |
182cf5a9 | 1536 | expression (an MEM_REF through an SSA_NAME) possibly insert the |
af4f74fa | 1537 | expression into the set NONTRAP or the hash table of seen expressions. |
1538 | STORE is true if this expression is on the LHS, otherwise it's on | |
1539 | the RHS. */ | |
c1f445d2 | 1540 | void |
1541 | nontrapping_dom_walker::add_or_mark_expr (basic_block bb, tree exp, bool store) | |
e6d0e152 | 1542 | { |
963aee26 | 1543 | HOST_WIDE_INT size; |
1544 | ||
182cf5a9 | 1545 | if (TREE_CODE (exp) == MEM_REF |
963aee26 | 1546 | && TREE_CODE (TREE_OPERAND (exp, 0)) == SSA_NAME |
e913b5cd | 1547 | && tree_fits_shwi_p (TREE_OPERAND (exp, 1)) |
963aee26 | 1548 | && (size = int_size_in_bytes (TREE_TYPE (exp))) > 0) |
e6d0e152 | 1549 | { |
1550 | tree name = TREE_OPERAND (exp, 0); | |
1551 | struct name_to_bb map; | |
d9dd21a8 | 1552 | name_to_bb **slot; |
af4f74fa | 1553 | struct name_to_bb *n2bb; |
e6d0e152 | 1554 | basic_block found_bb = 0; |
1555 | ||
182cf5a9 | 1556 | /* Try to find the last seen MEM_REF through the same |
e6d0e152 | 1557 | SSA_NAME, which can trap. */ |
963aee26 | 1558 | map.ssa_name_ver = SSA_NAME_VERSION (name); |
42540642 | 1559 | map.phase = 0; |
e6d0e152 | 1560 | map.bb = 0; |
af4f74fa | 1561 | map.store = store; |
e913b5cd | 1562 | map.offset = tree_to_shwi (TREE_OPERAND (exp, 1)); |
963aee26 | 1563 | map.size = size; |
1564 | ||
c1f445d2 | 1565 | slot = m_seen_ssa_names.find_slot (&map, INSERT); |
d9dd21a8 | 1566 | n2bb = *slot; |
42540642 | 1567 | if (n2bb && n2bb->phase >= nt_call_phase) |
af4f74fa | 1568 | found_bb = n2bb->bb; |
e6d0e152 | 1569 | |
182cf5a9 | 1570 | /* If we've found a trapping MEM_REF, _and_ it dominates EXP |
e6d0e152 | 1571 | (it's in a basic block on the path from us to the dominator root) |
1572 | then we can't trap. */ | |
42540642 | 1573 | if (found_bb && (((size_t)found_bb->aux) & 1) == 1) |
e6d0e152 | 1574 | { |
c1f445d2 | 1575 | pointer_set_insert (m_nontrapping, exp); |
e6d0e152 | 1576 | } |
1577 | else | |
1578 | { | |
1579 | /* EXP might trap, so insert it into the hash table. */ | |
af4f74fa | 1580 | if (n2bb) |
e6d0e152 | 1581 | { |
42540642 | 1582 | n2bb->phase = nt_call_phase; |
af4f74fa | 1583 | n2bb->bb = bb; |
e6d0e152 | 1584 | } |
1585 | else | |
1586 | { | |
af4f74fa | 1587 | n2bb = XNEW (struct name_to_bb); |
963aee26 | 1588 | n2bb->ssa_name_ver = SSA_NAME_VERSION (name); |
42540642 | 1589 | n2bb->phase = nt_call_phase; |
af4f74fa | 1590 | n2bb->bb = bb; |
1591 | n2bb->store = store; | |
963aee26 | 1592 | n2bb->offset = map.offset; |
1593 | n2bb->size = size; | |
af4f74fa | 1594 | *slot = n2bb; |
e6d0e152 | 1595 | } |
1596 | } | |
1597 | } | |
1598 | } | |
1599 | ||
e6d0e152 | 1600 | /* This is the entry point of gathering non trapping memory accesses. |
1601 | It will do a dominator walk over the whole function, and it will | |
1602 | make use of the bb->aux pointers. It returns a set of trees | |
182cf5a9 | 1603 | (the MEM_REFs itself) which can't trap. */ |
e6d0e152 | 1604 | static struct pointer_set_t * |
1605 | get_non_trapping (void) | |
1606 | { | |
42540642 | 1607 | nt_call_phase = 0; |
54c91640 | 1608 | pointer_set_t *nontrap = pointer_set_create (); |
e6d0e152 | 1609 | /* We're going to do a dominator walk, so ensure that we have |
1610 | dominance information. */ | |
1611 | calculate_dominance_info (CDI_DOMINATORS); | |
1612 | ||
54c91640 | 1613 | nontrapping_dom_walker (CDI_DOMINATORS, nontrap) |
1614 | .walk (cfun->cfg->x_entry_block_ptr); | |
1615 | ||
42540642 | 1616 | clear_aux_for_blocks (); |
e6d0e152 | 1617 | return nontrap; |
1618 | } | |
1619 | ||
1620 | /* Do the main work of conditional store replacement. We already know | |
1621 | that the recognized pattern looks like so: | |
1622 | ||
1623 | split: | |
1624 | if (cond) goto MIDDLE_BB; else goto JOIN_BB (edge E1) | |
1625 | MIDDLE_BB: | |
1626 | something | |
1627 | fallthrough (edge E0) | |
1628 | JOIN_BB: | |
1629 | some more | |
1630 | ||
1631 | We check that MIDDLE_BB contains only one store, that that store | |
1632 | doesn't trap (not via NOTRAP, but via checking if an access to the same | |
1633 | memory location dominates us) and that the store has a "simple" RHS. */ | |
1634 | ||
1635 | static bool | |
1636 | cond_store_replacement (basic_block middle_bb, basic_block join_bb, | |
1637 | edge e0, edge e1, struct pointer_set_t *nontrap) | |
1638 | { | |
75a70cf9 | 1639 | gimple assign = last_and_only_stmt (middle_bb); |
03d37e4e | 1640 | tree lhs, rhs, name, name2; |
75a70cf9 | 1641 | gimple newphi, new_stmt; |
1642 | gimple_stmt_iterator gsi; | |
efbcb6de | 1643 | source_location locus; |
e6d0e152 | 1644 | |
1645 | /* Check if middle_bb contains of only one store. */ | |
1646 | if (!assign | |
6cc085b6 | 1647 | || !gimple_assign_single_p (assign) |
1648 | || gimple_has_volatile_ops (assign)) | |
e6d0e152 | 1649 | return false; |
1650 | ||
efbcb6de | 1651 | locus = gimple_location (assign); |
75a70cf9 | 1652 | lhs = gimple_assign_lhs (assign); |
1653 | rhs = gimple_assign_rhs1 (assign); | |
182cf5a9 | 1654 | if (TREE_CODE (lhs) != MEM_REF |
91cf53d5 | 1655 | || TREE_CODE (TREE_OPERAND (lhs, 0)) != SSA_NAME |
3211fa0a | 1656 | || !is_gimple_reg_type (TREE_TYPE (lhs))) |
e6d0e152 | 1657 | return false; |
91cf53d5 | 1658 | |
e6d0e152 | 1659 | /* Prove that we can move the store down. We could also check |
1660 | TREE_THIS_NOTRAP here, but in that case we also could move stores, | |
1661 | whose value is not available readily, which we want to avoid. */ | |
1662 | if (!pointer_set_contains (nontrap, lhs)) | |
1663 | return false; | |
1664 | ||
1665 | /* Now we've checked the constraints, so do the transformation: | |
1666 | 1) Remove the single store. */ | |
75a70cf9 | 1667 | gsi = gsi_for_stmt (assign); |
3211fa0a | 1668 | unlink_stmt_vdef (assign); |
75a70cf9 | 1669 | gsi_remove (&gsi, true); |
91cf53d5 | 1670 | release_defs (assign); |
e6d0e152 | 1671 | |
03d37e4e | 1672 | /* 2) Insert a load from the memory of the store to the temporary |
e6d0e152 | 1673 | on the edge which did not contain the store. */ |
1674 | lhs = unshare_expr (lhs); | |
03d37e4e | 1675 | name = make_temp_ssa_name (TREE_TYPE (lhs), NULL, "cstore"); |
1676 | new_stmt = gimple_build_assign (name, lhs); | |
efbcb6de | 1677 | gimple_set_location (new_stmt, locus); |
75a70cf9 | 1678 | gsi_insert_on_edge (e1, new_stmt); |
e6d0e152 | 1679 | |
03d37e4e | 1680 | /* 3) Create a PHI node at the join block, with one argument |
e6d0e152 | 1681 | holding the old RHS, and the other holding the temporary |
1682 | where we stored the old memory contents. */ | |
03d37e4e | 1683 | name2 = make_temp_ssa_name (TREE_TYPE (lhs), NULL, "cstore"); |
1684 | newphi = create_phi_node (name2, join_bb); | |
60d535d2 | 1685 | add_phi_arg (newphi, rhs, e0, locus); |
1686 | add_phi_arg (newphi, name, e1, locus); | |
e6d0e152 | 1687 | |
1688 | lhs = unshare_expr (lhs); | |
75a70cf9 | 1689 | new_stmt = gimple_build_assign (lhs, PHI_RESULT (newphi)); |
e6d0e152 | 1690 | |
03d37e4e | 1691 | /* 4) Insert that PHI node. */ |
75a70cf9 | 1692 | gsi = gsi_after_labels (join_bb); |
1693 | if (gsi_end_p (gsi)) | |
e6d0e152 | 1694 | { |
75a70cf9 | 1695 | gsi = gsi_last_bb (join_bb); |
1696 | gsi_insert_after (&gsi, new_stmt, GSI_NEW_STMT); | |
e6d0e152 | 1697 | } |
1698 | else | |
75a70cf9 | 1699 | gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT); |
e6d0e152 | 1700 | |
1701 | return true; | |
1702 | } | |
4ee9c684 | 1703 | |
ec611e12 | 1704 | /* Do the main work of conditional store replacement. */ |
91cf53d5 | 1705 | |
1706 | static bool | |
ec611e12 | 1707 | cond_if_else_store_replacement_1 (basic_block then_bb, basic_block else_bb, |
1708 | basic_block join_bb, gimple then_assign, | |
1709 | gimple else_assign) | |
91cf53d5 | 1710 | { |
03d37e4e | 1711 | tree lhs_base, lhs, then_rhs, else_rhs, name; |
91cf53d5 | 1712 | source_location then_locus, else_locus; |
1713 | gimple_stmt_iterator gsi; | |
1714 | gimple newphi, new_stmt; | |
1715 | ||
91cf53d5 | 1716 | if (then_assign == NULL |
1717 | || !gimple_assign_single_p (then_assign) | |
3c25489e | 1718 | || gimple_clobber_p (then_assign) |
6cc085b6 | 1719 | || gimple_has_volatile_ops (then_assign) |
91cf53d5 | 1720 | || else_assign == NULL |
3c25489e | 1721 | || !gimple_assign_single_p (else_assign) |
6cc085b6 | 1722 | || gimple_clobber_p (else_assign) |
1723 | || gimple_has_volatile_ops (else_assign)) | |
91cf53d5 | 1724 | return false; |
1725 | ||
1726 | lhs = gimple_assign_lhs (then_assign); | |
1727 | if (!is_gimple_reg_type (TREE_TYPE (lhs)) | |
1728 | || !operand_equal_p (lhs, gimple_assign_lhs (else_assign), 0)) | |
1729 | return false; | |
1730 | ||
1731 | lhs_base = get_base_address (lhs); | |
1732 | if (lhs_base == NULL_TREE | |
1733 | || (!DECL_P (lhs_base) && TREE_CODE (lhs_base) != MEM_REF)) | |
1734 | return false; | |
1735 | ||
1736 | then_rhs = gimple_assign_rhs1 (then_assign); | |
1737 | else_rhs = gimple_assign_rhs1 (else_assign); | |
1738 | then_locus = gimple_location (then_assign); | |
1739 | else_locus = gimple_location (else_assign); | |
1740 | ||
1741 | /* Now we've checked the constraints, so do the transformation: | |
1742 | 1) Remove the stores. */ | |
1743 | gsi = gsi_for_stmt (then_assign); | |
1744 | unlink_stmt_vdef (then_assign); | |
1745 | gsi_remove (&gsi, true); | |
1746 | release_defs (then_assign); | |
1747 | ||
1748 | gsi = gsi_for_stmt (else_assign); | |
1749 | unlink_stmt_vdef (else_assign); | |
1750 | gsi_remove (&gsi, true); | |
1751 | release_defs (else_assign); | |
1752 | ||
03d37e4e | 1753 | /* 2) Create a PHI node at the join block, with one argument |
91cf53d5 | 1754 | holding the old RHS, and the other holding the temporary |
1755 | where we stored the old memory contents. */ | |
03d37e4e | 1756 | name = make_temp_ssa_name (TREE_TYPE (lhs), NULL, "cstore"); |
1757 | newphi = create_phi_node (name, join_bb); | |
60d535d2 | 1758 | add_phi_arg (newphi, then_rhs, EDGE_SUCC (then_bb, 0), then_locus); |
1759 | add_phi_arg (newphi, else_rhs, EDGE_SUCC (else_bb, 0), else_locus); | |
91cf53d5 | 1760 | |
1761 | new_stmt = gimple_build_assign (lhs, PHI_RESULT (newphi)); | |
1762 | ||
03d37e4e | 1763 | /* 3) Insert that PHI node. */ |
91cf53d5 | 1764 | gsi = gsi_after_labels (join_bb); |
1765 | if (gsi_end_p (gsi)) | |
1766 | { | |
1767 | gsi = gsi_last_bb (join_bb); | |
1768 | gsi_insert_after (&gsi, new_stmt, GSI_NEW_STMT); | |
1769 | } | |
1770 | else | |
1771 | gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT); | |
1772 | ||
1773 | return true; | |
1774 | } | |
1775 | ||
ec611e12 | 1776 | /* Conditional store replacement. We already know |
1777 | that the recognized pattern looks like so: | |
1778 | ||
1779 | split: | |
1780 | if (cond) goto THEN_BB; else goto ELSE_BB (edge E1) | |
1781 | THEN_BB: | |
1782 | ... | |
1783 | X = Y; | |
1784 | ... | |
1785 | goto JOIN_BB; | |
1786 | ELSE_BB: | |
1787 | ... | |
1788 | X = Z; | |
1789 | ... | |
1790 | fallthrough (edge E0) | |
1791 | JOIN_BB: | |
1792 | some more | |
1793 | ||
1794 | We check that it is safe to sink the store to JOIN_BB by verifying that | |
1795 | there are no read-after-write or write-after-write dependencies in | |
1796 | THEN_BB and ELSE_BB. */ | |
1797 | ||
1798 | static bool | |
1799 | cond_if_else_store_replacement (basic_block then_bb, basic_block else_bb, | |
1800 | basic_block join_bb) | |
1801 | { | |
1802 | gimple then_assign = last_and_only_stmt (then_bb); | |
1803 | gimple else_assign = last_and_only_stmt (else_bb); | |
f1f41a6c | 1804 | vec<data_reference_p> then_datarefs, else_datarefs; |
1805 | vec<ddr_p> then_ddrs, else_ddrs; | |
ec611e12 | 1806 | gimple then_store, else_store; |
1807 | bool found, ok = false, res; | |
1808 | struct data_dependence_relation *ddr; | |
1809 | data_reference_p then_dr, else_dr; | |
1810 | int i, j; | |
1811 | tree then_lhs, else_lhs; | |
ec611e12 | 1812 | basic_block blocks[3]; |
1813 | ||
1814 | if (MAX_STORES_TO_SINK == 0) | |
1815 | return false; | |
1816 | ||
1817 | /* Handle the case with single statement in THEN_BB and ELSE_BB. */ | |
1818 | if (then_assign && else_assign) | |
1819 | return cond_if_else_store_replacement_1 (then_bb, else_bb, join_bb, | |
1820 | then_assign, else_assign); | |
1821 | ||
1822 | /* Find data references. */ | |
f1f41a6c | 1823 | then_datarefs.create (1); |
1824 | else_datarefs.create (1); | |
ec611e12 | 1825 | if ((find_data_references_in_bb (NULL, then_bb, &then_datarefs) |
1826 | == chrec_dont_know) | |
f1f41a6c | 1827 | || !then_datarefs.length () |
ec611e12 | 1828 | || (find_data_references_in_bb (NULL, else_bb, &else_datarefs) |
c71d3c24 | 1829 | == chrec_dont_know) |
f1f41a6c | 1830 | || !else_datarefs.length ()) |
ec611e12 | 1831 | { |
1832 | free_data_refs (then_datarefs); | |
1833 | free_data_refs (else_datarefs); | |
1834 | return false; | |
1835 | } | |
1836 | ||
1837 | /* Find pairs of stores with equal LHS. */ | |
4997014d | 1838 | auto_vec<gimple, 1> then_stores, else_stores; |
f1f41a6c | 1839 | FOR_EACH_VEC_ELT (then_datarefs, i, then_dr) |
ec611e12 | 1840 | { |
1841 | if (DR_IS_READ (then_dr)) | |
1842 | continue; | |
1843 | ||
1844 | then_store = DR_STMT (then_dr); | |
728dcc71 | 1845 | then_lhs = gimple_get_lhs (then_store); |
c71d3c24 | 1846 | if (then_lhs == NULL_TREE) |
1847 | continue; | |
ec611e12 | 1848 | found = false; |
1849 | ||
f1f41a6c | 1850 | FOR_EACH_VEC_ELT (else_datarefs, j, else_dr) |
ec611e12 | 1851 | { |
1852 | if (DR_IS_READ (else_dr)) | |
1853 | continue; | |
1854 | ||
1855 | else_store = DR_STMT (else_dr); | |
728dcc71 | 1856 | else_lhs = gimple_get_lhs (else_store); |
c71d3c24 | 1857 | if (else_lhs == NULL_TREE) |
1858 | continue; | |
ec611e12 | 1859 | |
1860 | if (operand_equal_p (then_lhs, else_lhs, 0)) | |
1861 | { | |
1862 | found = true; | |
1863 | break; | |
1864 | } | |
1865 | } | |
1866 | ||
1867 | if (!found) | |
1868 | continue; | |
1869 | ||
f1f41a6c | 1870 | then_stores.safe_push (then_store); |
1871 | else_stores.safe_push (else_store); | |
ec611e12 | 1872 | } |
1873 | ||
1874 | /* No pairs of stores found. */ | |
f1f41a6c | 1875 | if (!then_stores.length () |
1876 | || then_stores.length () > (unsigned) MAX_STORES_TO_SINK) | |
ec611e12 | 1877 | { |
1878 | free_data_refs (then_datarefs); | |
1879 | free_data_refs (else_datarefs); | |
ec611e12 | 1880 | return false; |
1881 | } | |
1882 | ||
1883 | /* Compute and check data dependencies in both basic blocks. */ | |
f1f41a6c | 1884 | then_ddrs.create (1); |
1885 | else_ddrs.create (1); | |
1886 | if (!compute_all_dependences (then_datarefs, &then_ddrs, | |
1e094109 | 1887 | vNULL, false) |
f1f41a6c | 1888 | || !compute_all_dependences (else_datarefs, &else_ddrs, |
1e094109 | 1889 | vNULL, false)) |
8b3fb720 | 1890 | { |
1891 | free_dependence_relations (then_ddrs); | |
1892 | free_dependence_relations (else_ddrs); | |
1893 | free_data_refs (then_datarefs); | |
1894 | free_data_refs (else_datarefs); | |
8b3fb720 | 1895 | return false; |
1896 | } | |
ec611e12 | 1897 | blocks[0] = then_bb; |
1898 | blocks[1] = else_bb; | |
1899 | blocks[2] = join_bb; | |
1900 | renumber_gimple_stmt_uids_in_blocks (blocks, 3); | |
1901 | ||
1902 | /* Check that there are no read-after-write or write-after-write dependencies | |
1903 | in THEN_BB. */ | |
f1f41a6c | 1904 | FOR_EACH_VEC_ELT (then_ddrs, i, ddr) |
ec611e12 | 1905 | { |
1906 | struct data_reference *dra = DDR_A (ddr); | |
1907 | struct data_reference *drb = DDR_B (ddr); | |
1908 | ||
1909 | if (DDR_ARE_DEPENDENT (ddr) != chrec_known | |
1910 | && ((DR_IS_READ (dra) && DR_IS_WRITE (drb) | |
1911 | && gimple_uid (DR_STMT (dra)) > gimple_uid (DR_STMT (drb))) | |
1912 | || (DR_IS_READ (drb) && DR_IS_WRITE (dra) | |
1913 | && gimple_uid (DR_STMT (drb)) > gimple_uid (DR_STMT (dra))) | |
1914 | || (DR_IS_WRITE (dra) && DR_IS_WRITE (drb)))) | |
1915 | { | |
1916 | free_dependence_relations (then_ddrs); | |
1917 | free_dependence_relations (else_ddrs); | |
2473bfb7 | 1918 | free_data_refs (then_datarefs); |
1919 | free_data_refs (else_datarefs); | |
ec611e12 | 1920 | return false; |
1921 | } | |
1922 | } | |
1923 | ||
1924 | /* Check that there are no read-after-write or write-after-write dependencies | |
1925 | in ELSE_BB. */ | |
f1f41a6c | 1926 | FOR_EACH_VEC_ELT (else_ddrs, i, ddr) |
ec611e12 | 1927 | { |
1928 | struct data_reference *dra = DDR_A (ddr); | |
1929 | struct data_reference *drb = DDR_B (ddr); | |
1930 | ||
1931 | if (DDR_ARE_DEPENDENT (ddr) != chrec_known | |
1932 | && ((DR_IS_READ (dra) && DR_IS_WRITE (drb) | |
1933 | && gimple_uid (DR_STMT (dra)) > gimple_uid (DR_STMT (drb))) | |
1934 | || (DR_IS_READ (drb) && DR_IS_WRITE (dra) | |
1935 | && gimple_uid (DR_STMT (drb)) > gimple_uid (DR_STMT (dra))) | |
1936 | || (DR_IS_WRITE (dra) && DR_IS_WRITE (drb)))) | |
1937 | { | |
1938 | free_dependence_relations (then_ddrs); | |
1939 | free_dependence_relations (else_ddrs); | |
2473bfb7 | 1940 | free_data_refs (then_datarefs); |
1941 | free_data_refs (else_datarefs); | |
ec611e12 | 1942 | return false; |
1943 | } | |
1944 | } | |
1945 | ||
1946 | /* Sink stores with same LHS. */ | |
f1f41a6c | 1947 | FOR_EACH_VEC_ELT (then_stores, i, then_store) |
ec611e12 | 1948 | { |
f1f41a6c | 1949 | else_store = else_stores[i]; |
ec611e12 | 1950 | res = cond_if_else_store_replacement_1 (then_bb, else_bb, join_bb, |
1951 | then_store, else_store); | |
1952 | ok = ok || res; | |
1953 | } | |
1954 | ||
1955 | free_dependence_relations (then_ddrs); | |
1956 | free_dependence_relations (else_ddrs); | |
2473bfb7 | 1957 | free_data_refs (then_datarefs); |
1958 | free_data_refs (else_datarefs); | |
ec611e12 | 1959 | |
1960 | return ok; | |
1961 | } | |
1962 | ||
239e9670 | 1963 | /* Return TRUE if STMT has a VUSE whose corresponding VDEF is in BB. */ |
1964 | ||
1965 | static bool | |
1966 | local_mem_dependence (gimple stmt, basic_block bb) | |
1967 | { | |
1968 | tree vuse = gimple_vuse (stmt); | |
1969 | gimple def; | |
1970 | ||
1971 | if (!vuse) | |
1972 | return false; | |
1973 | ||
1974 | def = SSA_NAME_DEF_STMT (vuse); | |
1975 | return (def && gimple_bb (def) == bb); | |
1976 | } | |
1977 | ||
1978 | /* Given a "diamond" control-flow pattern where BB0 tests a condition, | |
1979 | BB1 and BB2 are "then" and "else" blocks dependent on this test, | |
f32420fb | 1980 | and BB3 rejoins control flow following BB1 and BB2, look for |
239e9670 | 1981 | opportunities to hoist loads as follows. If BB3 contains a PHI of |
1982 | two loads, one each occurring in BB1 and BB2, and the loads are | |
1983 | provably of adjacent fields in the same structure, then move both | |
1984 | loads into BB0. Of course this can only be done if there are no | |
1985 | dependencies preventing such motion. | |
1986 | ||
1987 | One of the hoisted loads will always be speculative, so the | |
1988 | transformation is currently conservative: | |
1989 | ||
1990 | - The fields must be strictly adjacent. | |
1991 | - The two fields must occupy a single memory block that is | |
1992 | guaranteed to not cross a page boundary. | |
1993 | ||
1994 | The last is difficult to prove, as such memory blocks should be | |
1995 | aligned on the minimum of the stack alignment boundary and the | |
1996 | alignment guaranteed by heap allocation interfaces. Thus we rely | |
1997 | on a parameter for the alignment value. | |
1998 | ||
1999 | Provided a good value is used for the last case, the first | |
2000 | restriction could possibly be relaxed. */ | |
2001 | ||
2002 | static void | |
2003 | hoist_adjacent_loads (basic_block bb0, basic_block bb1, | |
2004 | basic_block bb2, basic_block bb3) | |
2005 | { | |
2006 | int param_align = PARAM_VALUE (PARAM_L1_CACHE_LINE_SIZE); | |
2007 | unsigned param_align_bits = (unsigned) (param_align * BITS_PER_UNIT); | |
2008 | gimple_stmt_iterator gsi; | |
2009 | ||
2010 | /* Walk the phis in bb3 looking for an opportunity. We are looking | |
2011 | for phis of two SSA names, one each of which is defined in bb1 and | |
2012 | bb2. */ | |
2013 | for (gsi = gsi_start_phis (bb3); !gsi_end_p (gsi); gsi_next (&gsi)) | |
2014 | { | |
2015 | gimple phi_stmt = gsi_stmt (gsi); | |
2016 | gimple def1, def2, defswap; | |
2017 | tree arg1, arg2, ref1, ref2, field1, field2, fieldswap; | |
2018 | tree tree_offset1, tree_offset2, tree_size2, next; | |
2019 | int offset1, offset2, size2; | |
2020 | unsigned align1; | |
2021 | gimple_stmt_iterator gsi2; | |
2022 | basic_block bb_for_def1, bb_for_def2; | |
2023 | ||
7c782c9b | 2024 | if (gimple_phi_num_args (phi_stmt) != 2 |
2025 | || virtual_operand_p (gimple_phi_result (phi_stmt))) | |
239e9670 | 2026 | continue; |
2027 | ||
2028 | arg1 = gimple_phi_arg_def (phi_stmt, 0); | |
2029 | arg2 = gimple_phi_arg_def (phi_stmt, 1); | |
f32420fb | 2030 | |
239e9670 | 2031 | if (TREE_CODE (arg1) != SSA_NAME |
2032 | || TREE_CODE (arg2) != SSA_NAME | |
2033 | || SSA_NAME_IS_DEFAULT_DEF (arg1) | |
7c782c9b | 2034 | || SSA_NAME_IS_DEFAULT_DEF (arg2)) |
239e9670 | 2035 | continue; |
2036 | ||
2037 | def1 = SSA_NAME_DEF_STMT (arg1); | |
2038 | def2 = SSA_NAME_DEF_STMT (arg2); | |
2039 | ||
2040 | if ((gimple_bb (def1) != bb1 || gimple_bb (def2) != bb2) | |
2041 | && (gimple_bb (def2) != bb1 || gimple_bb (def1) != bb2)) | |
2042 | continue; | |
2043 | ||
2044 | /* Check the mode of the arguments to be sure a conditional move | |
2045 | can be generated for it. */ | |
935611bc | 2046 | if (optab_handler (movcc_optab, TYPE_MODE (TREE_TYPE (arg1))) |
2047 | == CODE_FOR_nothing) | |
239e9670 | 2048 | continue; |
2049 | ||
2050 | /* Both statements must be assignments whose RHS is a COMPONENT_REF. */ | |
2051 | if (!gimple_assign_single_p (def1) | |
6cc085b6 | 2052 | || !gimple_assign_single_p (def2) |
2053 | || gimple_has_volatile_ops (def1) | |
2054 | || gimple_has_volatile_ops (def2)) | |
239e9670 | 2055 | continue; |
2056 | ||
2057 | ref1 = gimple_assign_rhs1 (def1); | |
2058 | ref2 = gimple_assign_rhs1 (def2); | |
2059 | ||
2060 | if (TREE_CODE (ref1) != COMPONENT_REF | |
2061 | || TREE_CODE (ref2) != COMPONENT_REF) | |
2062 | continue; | |
2063 | ||
2064 | /* The zeroth operand of the two component references must be | |
2065 | identical. It is not sufficient to compare get_base_address of | |
2066 | the two references, because this could allow for different | |
2067 | elements of the same array in the two trees. It is not safe to | |
2068 | assume that the existence of one array element implies the | |
2069 | existence of a different one. */ | |
2070 | if (!operand_equal_p (TREE_OPERAND (ref1, 0), TREE_OPERAND (ref2, 0), 0)) | |
2071 | continue; | |
2072 | ||
2073 | field1 = TREE_OPERAND (ref1, 1); | |
2074 | field2 = TREE_OPERAND (ref2, 1); | |
2075 | ||
2076 | /* Check for field adjacency, and ensure field1 comes first. */ | |
2077 | for (next = DECL_CHAIN (field1); | |
2078 | next && TREE_CODE (next) != FIELD_DECL; | |
2079 | next = DECL_CHAIN (next)) | |
2080 | ; | |
2081 | ||
2082 | if (next != field2) | |
2083 | { | |
2084 | for (next = DECL_CHAIN (field2); | |
2085 | next && TREE_CODE (next) != FIELD_DECL; | |
2086 | next = DECL_CHAIN (next)) | |
2087 | ; | |
2088 | ||
2089 | if (next != field1) | |
2090 | continue; | |
2091 | ||
2092 | fieldswap = field1; | |
2093 | field1 = field2; | |
2094 | field2 = fieldswap; | |
2095 | defswap = def1; | |
2096 | def1 = def2; | |
2097 | def2 = defswap; | |
239e9670 | 2098 | } |
2099 | ||
7c74ee50 | 2100 | bb_for_def1 = gimple_bb (def1); |
2101 | bb_for_def2 = gimple_bb (def2); | |
2102 | ||
239e9670 | 2103 | /* Check for proper alignment of the first field. */ |
2104 | tree_offset1 = bit_position (field1); | |
2105 | tree_offset2 = bit_position (field2); | |
2106 | tree_size2 = DECL_SIZE (field2); | |
2107 | ||
e913b5cd | 2108 | if (!tree_fits_uhwi_p (tree_offset1) |
2109 | || !tree_fits_uhwi_p (tree_offset2) | |
2110 | || !tree_fits_uhwi_p (tree_size2)) | |
239e9670 | 2111 | continue; |
2112 | ||
e913b5cd | 2113 | offset1 = tree_to_uhwi (tree_offset1); |
2114 | offset2 = tree_to_uhwi (tree_offset2); | |
2115 | size2 = tree_to_uhwi (tree_size2); | |
239e9670 | 2116 | align1 = DECL_ALIGN (field1) % param_align_bits; |
2117 | ||
2118 | if (offset1 % BITS_PER_UNIT != 0) | |
2119 | continue; | |
2120 | ||
2121 | /* For profitability, the two field references should fit within | |
2122 | a single cache line. */ | |
2123 | if (align1 + offset2 - offset1 + size2 > param_align_bits) | |
2124 | continue; | |
2125 | ||
2126 | /* The two expressions cannot be dependent upon vdefs defined | |
2127 | in bb1/bb2. */ | |
2128 | if (local_mem_dependence (def1, bb_for_def1) | |
2129 | || local_mem_dependence (def2, bb_for_def2)) | |
2130 | continue; | |
2131 | ||
2132 | /* The conditions are satisfied; hoist the loads from bb1 and bb2 into | |
2133 | bb0. We hoist the first one first so that a cache miss is handled | |
2134 | efficiently regardless of hardware cache-fill policy. */ | |
2135 | gsi2 = gsi_for_stmt (def1); | |
2136 | gsi_move_to_bb_end (&gsi2, bb0); | |
2137 | gsi2 = gsi_for_stmt (def2); | |
2138 | gsi_move_to_bb_end (&gsi2, bb0); | |
2139 | ||
2140 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2141 | { | |
2142 | fprintf (dump_file, | |
2143 | "\nHoisting adjacent loads from %d and %d into %d: \n", | |
2144 | bb_for_def1->index, bb_for_def2->index, bb0->index); | |
2145 | print_gimple_stmt (dump_file, def1, 0, TDF_VOPS|TDF_MEMSYMS); | |
2146 | print_gimple_stmt (dump_file, def2, 0, TDF_VOPS|TDF_MEMSYMS); | |
2147 | } | |
2148 | } | |
2149 | } | |
2150 | ||
2151 | /* Determine whether we should attempt to hoist adjacent loads out of | |
2152 | diamond patterns in pass_phiopt. Always hoist loads if | |
2153 | -fhoist-adjacent-loads is specified and the target machine has | |
6f0ddab1 | 2154 | both a conditional move instruction and a defined cache line size. */ |
239e9670 | 2155 | |
2156 | static bool | |
2157 | gate_hoist_loads (void) | |
2158 | { | |
6f0ddab1 | 2159 | return (flag_hoist_adjacent_loads == 1 |
2160 | && PARAM_VALUE (PARAM_L1_CACHE_LINE_SIZE) | |
2161 | && HAVE_conditional_move); | |
239e9670 | 2162 | } |
2163 | ||
65b0537f | 2164 | /* This pass tries to replaces an if-then-else block with an |
2165 | assignment. We have four kinds of transformations. Some of these | |
2166 | transformations are also performed by the ifcvt RTL optimizer. | |
2167 | ||
2168 | Conditional Replacement | |
2169 | ----------------------- | |
2170 | ||
2171 | This transformation, implemented in conditional_replacement, | |
2172 | replaces | |
2173 | ||
2174 | bb0: | |
2175 | if (cond) goto bb2; else goto bb1; | |
2176 | bb1: | |
2177 | bb2: | |
2178 | x = PHI <0 (bb1), 1 (bb0), ...>; | |
2179 | ||
2180 | with | |
2181 | ||
2182 | bb0: | |
2183 | x' = cond; | |
2184 | goto bb2; | |
2185 | bb2: | |
2186 | x = PHI <x' (bb0), ...>; | |
2187 | ||
2188 | We remove bb1 as it becomes unreachable. This occurs often due to | |
2189 | gimplification of conditionals. | |
2190 | ||
2191 | Value Replacement | |
2192 | ----------------- | |
2193 | ||
2194 | This transformation, implemented in value_replacement, replaces | |
2195 | ||
2196 | bb0: | |
2197 | if (a != b) goto bb2; else goto bb1; | |
2198 | bb1: | |
2199 | bb2: | |
2200 | x = PHI <a (bb1), b (bb0), ...>; | |
2201 | ||
2202 | with | |
2203 | ||
2204 | bb0: | |
2205 | bb2: | |
2206 | x = PHI <b (bb0), ...>; | |
2207 | ||
2208 | This opportunity can sometimes occur as a result of other | |
2209 | optimizations. | |
2210 | ||
2211 | ||
2212 | Another case caught by value replacement looks like this: | |
2213 | ||
2214 | bb0: | |
2215 | t1 = a == CONST; | |
2216 | t2 = b > c; | |
2217 | t3 = t1 & t2; | |
2218 | if (t3 != 0) goto bb1; else goto bb2; | |
2219 | bb1: | |
2220 | bb2: | |
2221 | x = PHI (CONST, a) | |
2222 | ||
2223 | Gets replaced with: | |
2224 | bb0: | |
2225 | bb2: | |
2226 | t1 = a == CONST; | |
2227 | t2 = b > c; | |
2228 | t3 = t1 & t2; | |
2229 | x = a; | |
2230 | ||
2231 | ABS Replacement | |
2232 | --------------- | |
2233 | ||
2234 | This transformation, implemented in abs_replacement, replaces | |
2235 | ||
2236 | bb0: | |
2237 | if (a >= 0) goto bb2; else goto bb1; | |
2238 | bb1: | |
2239 | x = -a; | |
2240 | bb2: | |
2241 | x = PHI <x (bb1), a (bb0), ...>; | |
2242 | ||
2243 | with | |
2244 | ||
2245 | bb0: | |
2246 | x' = ABS_EXPR< a >; | |
2247 | bb2: | |
2248 | x = PHI <x' (bb0), ...>; | |
2249 | ||
2250 | MIN/MAX Replacement | |
2251 | ------------------- | |
2252 | ||
2253 | This transformation, minmax_replacement replaces | |
2254 | ||
2255 | bb0: | |
2256 | if (a <= b) goto bb2; else goto bb1; | |
2257 | bb1: | |
2258 | bb2: | |
2259 | x = PHI <b (bb1), a (bb0), ...>; | |
2260 | ||
2261 | with | |
2262 | ||
2263 | bb0: | |
2264 | x' = MIN_EXPR (a, b) | |
2265 | bb2: | |
2266 | x = PHI <x' (bb0), ...>; | |
2267 | ||
2268 | A similar transformation is done for MAX_EXPR. | |
2269 | ||
2270 | ||
2271 | This pass also performs a fifth transformation of a slightly different | |
2272 | flavor. | |
2273 | ||
2274 | Adjacent Load Hoisting | |
2275 | ---------------------- | |
2276 | ||
2277 | This transformation replaces | |
2278 | ||
2279 | bb0: | |
2280 | if (...) goto bb2; else goto bb1; | |
2281 | bb1: | |
2282 | x1 = (<expr>).field1; | |
2283 | goto bb3; | |
2284 | bb2: | |
2285 | x2 = (<expr>).field2; | |
2286 | bb3: | |
2287 | # x = PHI <x1, x2>; | |
2288 | ||
2289 | with | |
2290 | ||
2291 | bb0: | |
2292 | x1 = (<expr>).field1; | |
2293 | x2 = (<expr>).field2; | |
2294 | if (...) goto bb2; else goto bb1; | |
2295 | bb1: | |
2296 | goto bb3; | |
2297 | bb2: | |
2298 | bb3: | |
2299 | # x = PHI <x1, x2>; | |
2300 | ||
2301 | The purpose of this transformation is to enable generation of conditional | |
2302 | move instructions such as Intel CMOVE or PowerPC ISEL. Because one of | |
2303 | the loads is speculative, the transformation is restricted to very | |
2304 | specific cases to avoid introducing a page fault. We are looking for | |
2305 | the common idiom: | |
2306 | ||
2307 | if (...) | |
2308 | x = y->left; | |
2309 | else | |
2310 | x = y->right; | |
2311 | ||
2312 | where left and right are typically adjacent pointers in a tree structure. */ | |
20e5647c | 2313 | |
cbe8bda8 | 2314 | namespace { |
2315 | ||
2316 | const pass_data pass_data_phiopt = | |
4ee9c684 | 2317 | { |
cbe8bda8 | 2318 | GIMPLE_PASS, /* type */ |
2319 | "phiopt", /* name */ | |
2320 | OPTGROUP_NONE, /* optinfo_flags */ | |
cbe8bda8 | 2321 | TV_TREE_PHIOPT, /* tv_id */ |
2322 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
2323 | 0, /* properties_provided */ | |
2324 | 0, /* properties_destroyed */ | |
2325 | 0, /* todo_flags_start */ | |
8b88439e | 2326 | 0, /* todo_flags_finish */ |
4ee9c684 | 2327 | }; |
e6d0e152 | 2328 | |
cbe8bda8 | 2329 | class pass_phiopt : public gimple_opt_pass |
2330 | { | |
2331 | public: | |
9af5ce0c | 2332 | pass_phiopt (gcc::context *ctxt) |
2333 | : gimple_opt_pass (pass_data_phiopt, ctxt) | |
cbe8bda8 | 2334 | {} |
2335 | ||
2336 | /* opt_pass methods: */ | |
ae84f584 | 2337 | opt_pass * clone () { return new pass_phiopt (m_ctxt); } |
3dac50cc | 2338 | virtual bool gate (function *) { return flag_ssa_phiopt; } |
65b0537f | 2339 | virtual unsigned int execute (function *) |
2340 | { | |
2341 | return tree_ssa_phiopt_worker (false, gate_hoist_loads ()); | |
2342 | } | |
cbe8bda8 | 2343 | |
2344 | }; // class pass_phiopt | |
2345 | ||
2346 | } // anon namespace | |
2347 | ||
2348 | gimple_opt_pass * | |
2349 | make_pass_phiopt (gcc::context *ctxt) | |
2350 | { | |
2351 | return new pass_phiopt (ctxt); | |
2352 | } | |
2353 | ||
cbe8bda8 | 2354 | namespace { |
2355 | ||
2356 | const pass_data pass_data_cselim = | |
e6d0e152 | 2357 | { |
cbe8bda8 | 2358 | GIMPLE_PASS, /* type */ |
2359 | "cselim", /* name */ | |
2360 | OPTGROUP_NONE, /* optinfo_flags */ | |
cbe8bda8 | 2361 | TV_TREE_PHIOPT, /* tv_id */ |
2362 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
2363 | 0, /* properties_provided */ | |
2364 | 0, /* properties_destroyed */ | |
2365 | 0, /* todo_flags_start */ | |
8b88439e | 2366 | 0, /* todo_flags_finish */ |
e6d0e152 | 2367 | }; |
cbe8bda8 | 2368 | |
2369 | class pass_cselim : public gimple_opt_pass | |
2370 | { | |
2371 | public: | |
9af5ce0c | 2372 | pass_cselim (gcc::context *ctxt) |
2373 | : gimple_opt_pass (pass_data_cselim, ctxt) | |
cbe8bda8 | 2374 | {} |
2375 | ||
2376 | /* opt_pass methods: */ | |
31315c24 | 2377 | virtual bool gate (function *) { return flag_tree_cselim; } |
65b0537f | 2378 | virtual unsigned int execute (function *) { return tree_ssa_cs_elim (); } |
cbe8bda8 | 2379 | |
2380 | }; // class pass_cselim | |
2381 | ||
2382 | } // anon namespace | |
2383 | ||
2384 | gimple_opt_pass * | |
2385 | make_pass_cselim (gcc::context *ctxt) | |
2386 | { | |
2387 | return new pass_cselim (ctxt); | |
2388 | } |