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4ee9c684 | 1 | /* Optimization of PHI nodes by converting them into straightline code. |
d353bf18 | 2 | Copyright (C) 2004-2015 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" |
b20a8bb4 | 25 | #include "hash-set.h" |
b20a8bb4 | 26 | #include "vec.h" |
b20a8bb4 | 27 | #include "input.h" |
28 | #include "alias.h" | |
29 | #include "symtab.h" | |
b20a8bb4 | 30 | #include "inchash.h" |
4ee9c684 | 31 | #include "tree.h" |
b20a8bb4 | 32 | #include "fold-const.h" |
9ed99284 | 33 | #include "stor-layout.h" |
0beac6fc | 34 | #include "flags.h" |
4ee9c684 | 35 | #include "tm_p.h" |
94ea8568 | 36 | #include "predict.h" |
94ea8568 | 37 | #include "hard-reg-set.h" |
94ea8568 | 38 | #include "function.h" |
39 | #include "dominance.h" | |
40 | #include "cfg.h" | |
41 | #include "cfganal.h" | |
42 | #include "basic-block.h" | |
bc61cadb | 43 | #include "tree-ssa-alias.h" |
44 | #include "internal-fn.h" | |
45 | #include "gimple-expr.h" | |
46 | #include "is-a.h" | |
073c1fd5 | 47 | #include "gimple.h" |
a8783bee | 48 | #include "gimplify.h" |
dcf1a1ec | 49 | #include "gimple-iterator.h" |
e795d6e1 | 50 | #include "gimplify-me.h" |
073c1fd5 | 51 | #include "gimple-ssa.h" |
52 | #include "tree-cfg.h" | |
53 | #include "tree-phinodes.h" | |
54 | #include "ssa-iterators.h" | |
9ed99284 | 55 | #include "stringpool.h" |
073c1fd5 | 56 | #include "tree-ssanames.h" |
d53441c8 | 57 | #include "hashtab.h" |
58 | #include "rtl.h" | |
59 | #include "statistics.h" | |
d53441c8 | 60 | #include "insn-config.h" |
61 | #include "expmed.h" | |
62 | #include "dojump.h" | |
63 | #include "explow.h" | |
64 | #include "calls.h" | |
65 | #include "emit-rtl.h" | |
66 | #include "varasm.h" | |
67 | #include "stmt.h" | |
9ed99284 | 68 | #include "expr.h" |
073c1fd5 | 69 | #include "tree-dfa.h" |
4ee9c684 | 70 | #include "tree-pass.h" |
4ee9c684 | 71 | #include "langhooks.h" |
e6d0e152 | 72 | #include "domwalk.h" |
ec611e12 | 73 | #include "cfgloop.h" |
74 | #include "tree-data-ref.h" | |
239e9670 | 75 | #include "gimple-pretty-print.h" |
34517c64 | 76 | #include "insn-codes.h" |
239e9670 | 77 | #include "optabs.h" |
f6568ea4 | 78 | #include "tree-scalar-evolution.h" |
b6814ca0 | 79 | #include "tree-inline.h" |
239e9670 | 80 | |
239e9670 | 81 | static unsigned int tree_ssa_phiopt_worker (bool, bool); |
a4844041 | 82 | static bool conditional_replacement (basic_block, basic_block, |
1a91d914 | 83 | edge, edge, gphi *, tree, tree); |
fb9912ea | 84 | static int value_replacement (basic_block, basic_block, |
85 | edge, edge, gimple, tree, tree); | |
a4844041 | 86 | static bool minmax_replacement (basic_block, basic_block, |
75a70cf9 | 87 | edge, edge, gimple, tree, tree); |
a4844041 | 88 | static bool abs_replacement (basic_block, basic_block, |
75a70cf9 | 89 | edge, edge, gimple, tree, tree); |
e6d0e152 | 90 | static bool cond_store_replacement (basic_block, basic_block, edge, edge, |
431205b7 | 91 | hash_set<tree> *); |
91cf53d5 | 92 | static bool cond_if_else_store_replacement (basic_block, basic_block, basic_block); |
431205b7 | 93 | static hash_set<tree> * get_non_trapping (); |
75a70cf9 | 94 | static void replace_phi_edge_with_variable (basic_block, edge, gimple, tree); |
239e9670 | 95 | static void hoist_adjacent_loads (basic_block, basic_block, |
96 | basic_block, basic_block); | |
97 | static bool gate_hoist_loads (void); | |
902929aa | 98 | |
e6d0e152 | 99 | /* This pass tries to transform conditional stores into unconditional |
100 | ones, enabling further simplifications with the simpler then and else | |
101 | blocks. In particular it replaces this: | |
102 | ||
103 | bb0: | |
104 | if (cond) goto bb2; else goto bb1; | |
105 | bb1: | |
91cf53d5 | 106 | *p = RHS; |
e6d0e152 | 107 | bb2: |
108 | ||
109 | with | |
110 | ||
111 | bb0: | |
112 | if (cond) goto bb1; else goto bb2; | |
113 | bb1: | |
114 | condtmp' = *p; | |
115 | bb2: | |
116 | condtmp = PHI <RHS, condtmp'> | |
91cf53d5 | 117 | *p = condtmp; |
e6d0e152 | 118 | |
119 | This transformation can only be done under several constraints, | |
91cf53d5 | 120 | documented below. It also replaces: |
121 | ||
122 | bb0: | |
123 | if (cond) goto bb2; else goto bb1; | |
124 | bb1: | |
125 | *p = RHS1; | |
126 | goto bb3; | |
127 | bb2: | |
128 | *p = RHS2; | |
129 | bb3: | |
130 | ||
131 | with | |
132 | ||
133 | bb0: | |
134 | if (cond) goto bb3; else goto bb1; | |
135 | bb1: | |
136 | bb3: | |
137 | condtmp = PHI <RHS1, RHS2> | |
138 | *p = condtmp; */ | |
e6d0e152 | 139 | |
140 | static unsigned int | |
141 | tree_ssa_cs_elim (void) | |
142 | { | |
f6568ea4 | 143 | unsigned todo; |
144 | /* ??? We are not interested in loop related info, but the following | |
145 | will create it, ICEing as we didn't init loops with pre-headers. | |
146 | An interfacing issue of find_data_references_in_bb. */ | |
147 | loop_optimizer_init (LOOPS_NORMAL); | |
148 | scev_initialize (); | |
149 | todo = tree_ssa_phiopt_worker (true, false); | |
150 | scev_finalize (); | |
151 | loop_optimizer_finalize (); | |
152 | return todo; | |
e6d0e152 | 153 | } |
154 | ||
c3597b05 | 155 | /* Return the singleton PHI in the SEQ of PHIs for edges E0 and E1. */ |
156 | ||
1a91d914 | 157 | static gphi * |
c3597b05 | 158 | single_non_singleton_phi_for_edges (gimple_seq seq, edge e0, edge e1) |
159 | { | |
160 | gimple_stmt_iterator i; | |
1a91d914 | 161 | gphi *phi = NULL; |
c3597b05 | 162 | if (gimple_seq_singleton_p (seq)) |
1a91d914 | 163 | return as_a <gphi *> (gsi_stmt (gsi_start (seq))); |
c3597b05 | 164 | for (i = gsi_start (seq); !gsi_end_p (i); gsi_next (&i)) |
165 | { | |
1a91d914 | 166 | gphi *p = as_a <gphi *> (gsi_stmt (i)); |
c3597b05 | 167 | /* If the PHI arguments are equal then we can skip this PHI. */ |
168 | if (operand_equal_for_phi_arg_p (gimple_phi_arg_def (p, e0->dest_idx), | |
169 | gimple_phi_arg_def (p, e1->dest_idx))) | |
170 | continue; | |
171 | ||
172 | /* If we already have a PHI that has the two edge arguments are | |
173 | different, then return it is not a singleton for these PHIs. */ | |
174 | if (phi) | |
175 | return NULL; | |
176 | ||
177 | phi = p; | |
178 | } | |
179 | return phi; | |
180 | } | |
181 | ||
e6d0e152 | 182 | /* The core routine of conditional store replacement and normal |
183 | phi optimizations. Both share much of the infrastructure in how | |
184 | to match applicable basic block patterns. DO_STORE_ELIM is true | |
239e9670 | 185 | when we want to do conditional store replacement, false otherwise. |
f32420fb | 186 | DO_HOIST_LOADS is true when we want to hoist adjacent loads out |
239e9670 | 187 | of diamond control flow patterns, false otherwise. */ |
e6d0e152 | 188 | static unsigned int |
239e9670 | 189 | tree_ssa_phiopt_worker (bool do_store_elim, bool do_hoist_loads) |
4ee9c684 | 190 | { |
191 | basic_block bb; | |
194899bf | 192 | basic_block *bb_order; |
193 | unsigned n, i; | |
1e4b21e3 | 194 | bool cfgchanged = false; |
431205b7 | 195 | hash_set<tree> *nontrap = 0; |
e6d0e152 | 196 | |
197 | if (do_store_elim) | |
03d37e4e | 198 | /* Calculate the set of non-trapping memory accesses. */ |
199 | nontrap = get_non_trapping (); | |
194899bf | 200 | |
201 | /* Search every basic block for COND_EXPR we may be able to optimize. | |
202 | ||
203 | We walk the blocks in order that guarantees that a block with | |
204 | a single predecessor is processed before the predecessor. | |
205 | This ensures that we collapse inner ifs before visiting the | |
206 | outer ones, and also that we do not try to visit a removed | |
207 | block. */ | |
ba4d2b2f | 208 | bb_order = single_pred_before_succ_order (); |
a28770e1 | 209 | n = n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS; |
4ee9c684 | 210 | |
48e1416a | 211 | for (i = 0; i < n; i++) |
4ee9c684 | 212 | { |
1a91d914 | 213 | gimple cond_stmt; |
214 | gphi *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 | { | |
1a91d914 | 325 | phi = as_a <gphi *> (gsi_stmt (gsi)); |
fb9912ea | 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; | |
355 | else if (minmax_replacement (bb, bb1, e1, e2, phi, arg0, arg1)) | |
356 | cfgchanged = true; | |
357 | } | |
194899bf | 358 | } |
359 | ||
360 | free (bb_order); | |
48e1416a | 361 | |
e6d0e152 | 362 | if (do_store_elim) |
431205b7 | 363 | delete nontrap; |
e6d0e152 | 364 | /* If the CFG has changed, we should cleanup the CFG. */ |
365 | if (cfgchanged && do_store_elim) | |
366 | { | |
367 | /* In cond-store replacement we have added some loads on edges | |
368 | and new VOPS (as we moved the store, and created a load). */ | |
75a70cf9 | 369 | gsi_commit_edge_inserts (); |
e6d0e152 | 370 | return TODO_cleanup_cfg | TODO_update_ssa_only_virtuals; |
371 | } | |
372 | else if (cfgchanged) | |
373 | return TODO_cleanup_cfg; | |
374 | return 0; | |
194899bf | 375 | } |
376 | ||
fccee353 | 377 | /* Replace PHI node element whose edge is E in block BB with variable NEW. |
33784d89 | 378 | Remove the edge from COND_BLOCK which does not lead to BB (COND_BLOCK |
902929aa | 379 | is known to have two edges, one of which must reach BB). */ |
380 | ||
381 | static void | |
a4844041 | 382 | replace_phi_edge_with_variable (basic_block cond_block, |
75a70cf9 | 383 | edge e, gimple phi, tree new_tree) |
902929aa | 384 | { |
75a70cf9 | 385 | basic_block bb = gimple_bb (phi); |
0e1a77e1 | 386 | basic_block block_to_remove; |
75a70cf9 | 387 | gimple_stmt_iterator gsi; |
33784d89 | 388 | |
20e5647c | 389 | /* Change the PHI argument to new. */ |
f0d6e81c | 390 | SET_USE (PHI_ARG_DEF_PTR (phi, e->dest_idx), new_tree); |
0e1a77e1 | 391 | |
0e1a77e1 | 392 | /* Remove the empty basic block. */ |
cd665a06 | 393 | if (EDGE_SUCC (cond_block, 0)->dest == bb) |
902929aa | 394 | { |
cd665a06 | 395 | EDGE_SUCC (cond_block, 0)->flags |= EDGE_FALLTHRU; |
396 | EDGE_SUCC (cond_block, 0)->flags &= ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE); | |
81c5be57 | 397 | EDGE_SUCC (cond_block, 0)->probability = REG_BR_PROB_BASE; |
398 | EDGE_SUCC (cond_block, 0)->count += EDGE_SUCC (cond_block, 1)->count; | |
0e1a77e1 | 399 | |
cd665a06 | 400 | block_to_remove = EDGE_SUCC (cond_block, 1)->dest; |
902929aa | 401 | } |
402 | else | |
403 | { | |
cd665a06 | 404 | EDGE_SUCC (cond_block, 1)->flags |= EDGE_FALLTHRU; |
405 | EDGE_SUCC (cond_block, 1)->flags | |
902929aa | 406 | &= ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE); |
81c5be57 | 407 | EDGE_SUCC (cond_block, 1)->probability = REG_BR_PROB_BASE; |
408 | EDGE_SUCC (cond_block, 1)->count += EDGE_SUCC (cond_block, 0)->count; | |
0e1a77e1 | 409 | |
cd665a06 | 410 | block_to_remove = EDGE_SUCC (cond_block, 0)->dest; |
902929aa | 411 | } |
0e1a77e1 | 412 | delete_basic_block (block_to_remove); |
20e5647c | 413 | |
902929aa | 414 | /* Eliminate the COND_EXPR at the end of COND_BLOCK. */ |
75a70cf9 | 415 | gsi = gsi_last_bb (cond_block); |
416 | gsi_remove (&gsi, true); | |
20e5647c | 417 | |
902929aa | 418 | if (dump_file && (dump_flags & TDF_DETAILS)) |
419 | fprintf (dump_file, | |
420 | "COND_EXPR in block %d and PHI in block %d converted to straightline code.\n", | |
421 | cond_block->index, | |
422 | bb->index); | |
423 | } | |
424 | ||
425 | /* The function conditional_replacement does the main work of doing the | |
426 | conditional replacement. Return true if the replacement is done. | |
427 | Otherwise return false. | |
428 | BB is the basic block where the replacement is going to be done on. ARG0 | |
dac49aa5 | 429 | is argument 0 from PHI. Likewise for ARG1. */ |
902929aa | 430 | |
431 | static bool | |
33784d89 | 432 | conditional_replacement (basic_block cond_bb, basic_block middle_bb, |
1a91d914 | 433 | edge e0, edge e1, gphi *phi, |
33784d89 | 434 | tree arg0, tree arg1) |
902929aa | 435 | { |
436 | tree result; | |
1a91d914 | 437 | gimple stmt; |
438 | gassign *new_stmt; | |
75a70cf9 | 439 | tree cond; |
440 | gimple_stmt_iterator gsi; | |
902929aa | 441 | edge true_edge, false_edge; |
75a70cf9 | 442 | tree new_var, new_var2; |
678919fd | 443 | bool neg; |
902929aa | 444 | |
435e1a75 | 445 | /* FIXME: Gimplification of complex type is too hard for now. */ |
47b88316 | 446 | /* We aren't prepared to handle vectors either (and it is a question |
447 | if it would be worthwhile anyway). */ | |
448 | if (!(INTEGRAL_TYPE_P (TREE_TYPE (arg0)) | |
449 | || POINTER_TYPE_P (TREE_TYPE (arg0))) | |
450 | || !(INTEGRAL_TYPE_P (TREE_TYPE (arg1)) | |
451 | || POINTER_TYPE_P (TREE_TYPE (arg1)))) | |
435e1a75 | 452 | return false; |
453 | ||
678919fd | 454 | /* The PHI arguments have the constants 0 and 1, or 0 and -1, then |
455 | convert it to the conditional. */ | |
902929aa | 456 | if ((integer_zerop (arg0) && integer_onep (arg1)) |
457 | || (integer_zerop (arg1) && integer_onep (arg0))) | |
678919fd | 458 | neg = false; |
459 | else if ((integer_zerop (arg0) && integer_all_onesp (arg1)) | |
460 | || (integer_zerop (arg1) && integer_all_onesp (arg0))) | |
461 | neg = true; | |
902929aa | 462 | else |
463 | return false; | |
20e5647c | 464 | |
33784d89 | 465 | if (!empty_block_p (middle_bb)) |
902929aa | 466 | return false; |
20e5647c | 467 | |
75a70cf9 | 468 | /* At this point we know we have a GIMPLE_COND with two successors. |
2ab0a163 | 469 | One successor is BB, the other successor is an empty block which |
470 | falls through into BB. | |
20e5647c | 471 | |
2ab0a163 | 472 | There is a single PHI node at the join point (BB) and its arguments |
678919fd | 473 | are constants (0, 1) or (0, -1). |
20e5647c | 474 | |
2ab0a163 | 475 | So, given the condition COND, and the two PHI arguments, we can |
20e5647c | 476 | rewrite this PHI into non-branching code: |
477 | ||
2ab0a163 | 478 | dest = (COND) or dest = COND' |
20e5647c | 479 | |
2ab0a163 | 480 | We use the condition as-is if the argument associated with the |
481 | true edge has the value one or the argument associated with the | |
482 | false edge as the value zero. Note that those conditions are not | |
75a70cf9 | 483 | the same since only one of the outgoing edges from the GIMPLE_COND |
2ab0a163 | 484 | will directly reach BB and thus be associated with an argument. */ |
ae5a4794 | 485 | |
75a70cf9 | 486 | stmt = last_stmt (cond_bb); |
487 | result = PHI_RESULT (phi); | |
b2a02a0e | 488 | |
75a70cf9 | 489 | /* To handle special cases like floating point comparison, it is easier and |
490 | less error-prone to build a tree and gimplify it on the fly though it is | |
491 | less efficient. */ | |
6f9714b3 | 492 | cond = fold_build2_loc (gimple_location (stmt), |
493 | gimple_cond_code (stmt), boolean_type_node, | |
494 | gimple_cond_lhs (stmt), gimple_cond_rhs (stmt)); | |
4ee9c684 | 495 | |
75a70cf9 | 496 | /* We need to know which is the true edge and which is the false |
497 | edge so that we know when to invert the condition below. */ | |
498 | extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge); | |
499 | if ((e0 == true_edge && integer_zerop (arg0)) | |
678919fd | 500 | || (e0 == false_edge && !integer_zerop (arg0)) |
75a70cf9 | 501 | || (e1 == true_edge && integer_zerop (arg1)) |
678919fd | 502 | || (e1 == false_edge && !integer_zerop (arg1))) |
6f9714b3 | 503 | cond = fold_build1_loc (gimple_location (stmt), |
678919fd | 504 | TRUTH_NOT_EXPR, TREE_TYPE (cond), cond); |
505 | ||
506 | if (neg) | |
507 | { | |
508 | cond = fold_convert_loc (gimple_location (stmt), | |
509 | TREE_TYPE (result), cond); | |
510 | cond = fold_build1_loc (gimple_location (stmt), | |
511 | NEGATE_EXPR, TREE_TYPE (cond), cond); | |
512 | } | |
75a70cf9 | 513 | |
514 | /* Insert our new statements at the end of conditional block before the | |
515 | COND_STMT. */ | |
516 | gsi = gsi_for_stmt (stmt); | |
517 | new_var = force_gimple_operand_gsi (&gsi, cond, true, NULL, true, | |
518 | GSI_SAME_STMT); | |
519 | ||
520 | if (!useless_type_conversion_p (TREE_TYPE (result), TREE_TYPE (new_var))) | |
521 | { | |
efbcb6de | 522 | source_location locus_0, locus_1; |
523 | ||
f9e245b2 | 524 | new_var2 = make_ssa_name (TREE_TYPE (result)); |
e9cf809e | 525 | new_stmt = gimple_build_assign (new_var2, CONVERT_EXPR, new_var); |
75a70cf9 | 526 | gsi_insert_before (&gsi, new_stmt, GSI_SAME_STMT); |
527 | new_var = new_var2; | |
efbcb6de | 528 | |
529 | /* Set the locus to the first argument, unless is doesn't have one. */ | |
530 | locus_0 = gimple_phi_arg_location (phi, 0); | |
531 | locus_1 = gimple_phi_arg_location (phi, 1); | |
532 | if (locus_0 == UNKNOWN_LOCATION) | |
533 | locus_0 = locus_1; | |
534 | gimple_set_location (new_stmt, locus_0); | |
4ee9c684 | 535 | } |
20e5647c | 536 | |
75a70cf9 | 537 | replace_phi_edge_with_variable (cond_bb, e1, phi, new_var); |
902929aa | 538 | |
4ee9c684 | 539 | /* Note that we optimized this PHI. */ |
540 | return true; | |
541 | } | |
542 | ||
17b9476e | 543 | /* Update *ARG which is defined in STMT so that it contains the |
544 | computed value if that seems profitable. Return true if the | |
545 | statement is made dead by that rewriting. */ | |
546 | ||
547 | static bool | |
548 | jump_function_from_stmt (tree *arg, gimple stmt) | |
549 | { | |
550 | enum tree_code code = gimple_assign_rhs_code (stmt); | |
551 | if (code == ADDR_EXPR) | |
552 | { | |
553 | /* For arg = &p->i transform it to p, if possible. */ | |
554 | tree rhs1 = gimple_assign_rhs1 (stmt); | |
555 | HOST_WIDE_INT offset; | |
556 | tree tem = get_addr_base_and_unit_offset (TREE_OPERAND (rhs1, 0), | |
557 | &offset); | |
558 | if (tem | |
559 | && TREE_CODE (tem) == MEM_REF | |
796b6678 | 560 | && (mem_ref_offset (tem) + offset) == 0) |
17b9476e | 561 | { |
562 | *arg = TREE_OPERAND (tem, 0); | |
563 | return true; | |
564 | } | |
565 | } | |
566 | /* TODO: Much like IPA-CP jump-functions we want to handle constant | |
567 | additions symbolically here, and we'd need to update the comparison | |
568 | code that compares the arg + cst tuples in our caller. For now the | |
569 | code above exactly handles the VEC_BASE pattern from vec.h. */ | |
570 | return false; | |
571 | } | |
572 | ||
f32420fb | 573 | /* RHS is a source argument in a BIT_AND_EXPR which feeds a conditional |
574 | of the form SSA_NAME NE 0. | |
575 | ||
576 | If RHS is fed by a simple EQ_EXPR comparison of two values, see if | |
577 | the two input values of the EQ_EXPR match arg0 and arg1. | |
578 | ||
579 | If so update *code and return TRUE. Otherwise return FALSE. */ | |
580 | ||
581 | static bool | |
582 | rhs_is_fed_for_value_replacement (const_tree arg0, const_tree arg1, | |
583 | enum tree_code *code, const_tree rhs) | |
584 | { | |
585 | /* Obviously if RHS is not an SSA_NAME, we can't look at the defining | |
586 | statement. */ | |
587 | if (TREE_CODE (rhs) == SSA_NAME) | |
588 | { | |
589 | gimple def1 = SSA_NAME_DEF_STMT (rhs); | |
590 | ||
591 | /* Verify the defining statement has an EQ_EXPR on the RHS. */ | |
592 | if (is_gimple_assign (def1) && gimple_assign_rhs_code (def1) == EQ_EXPR) | |
593 | { | |
594 | /* Finally verify the source operands of the EQ_EXPR are equal | |
595 | to arg0 and arg1. */ | |
596 | tree op0 = gimple_assign_rhs1 (def1); | |
597 | tree op1 = gimple_assign_rhs2 (def1); | |
598 | if ((operand_equal_for_phi_arg_p (arg0, op0) | |
599 | && operand_equal_for_phi_arg_p (arg1, op1)) | |
600 | || (operand_equal_for_phi_arg_p (arg0, op1) | |
601 | && operand_equal_for_phi_arg_p (arg1, op0))) | |
602 | { | |
603 | /* We will perform the optimization. */ | |
604 | *code = gimple_assign_rhs_code (def1); | |
605 | return true; | |
606 | } | |
607 | } | |
608 | } | |
609 | return false; | |
610 | } | |
611 | ||
612 | /* Return TRUE if arg0/arg1 are equal to the rhs/lhs or lhs/rhs of COND. | |
613 | ||
614 | Also return TRUE if arg0/arg1 are equal to the source arguments of a | |
615 | an EQ comparison feeding a BIT_AND_EXPR which feeds COND. | |
616 | ||
617 | Return FALSE otherwise. */ | |
618 | ||
619 | static bool | |
620 | operand_equal_for_value_replacement (const_tree arg0, const_tree arg1, | |
621 | enum tree_code *code, gimple cond) | |
622 | { | |
623 | gimple def; | |
624 | tree lhs = gimple_cond_lhs (cond); | |
625 | tree rhs = gimple_cond_rhs (cond); | |
626 | ||
627 | if ((operand_equal_for_phi_arg_p (arg0, lhs) | |
628 | && operand_equal_for_phi_arg_p (arg1, rhs)) | |
629 | || (operand_equal_for_phi_arg_p (arg1, lhs) | |
630 | && operand_equal_for_phi_arg_p (arg0, rhs))) | |
631 | return true; | |
632 | ||
633 | /* Now handle more complex case where we have an EQ comparison | |
634 | which feeds a BIT_AND_EXPR which feeds COND. | |
635 | ||
636 | First verify that COND is of the form SSA_NAME NE 0. */ | |
637 | if (*code != NE_EXPR || !integer_zerop (rhs) | |
638 | || TREE_CODE (lhs) != SSA_NAME) | |
639 | return false; | |
640 | ||
641 | /* Now ensure that SSA_NAME is set by a BIT_AND_EXPR. */ | |
642 | def = SSA_NAME_DEF_STMT (lhs); | |
643 | if (!is_gimple_assign (def) || gimple_assign_rhs_code (def) != BIT_AND_EXPR) | |
644 | return false; | |
645 | ||
646 | /* Now verify arg0/arg1 correspond to the source arguments of an | |
647 | EQ comparison feeding the BIT_AND_EXPR. */ | |
648 | ||
649 | tree tmp = gimple_assign_rhs1 (def); | |
650 | if (rhs_is_fed_for_value_replacement (arg0, arg1, code, tmp)) | |
651 | return true; | |
652 | ||
653 | tmp = gimple_assign_rhs2 (def); | |
654 | if (rhs_is_fed_for_value_replacement (arg0, arg1, code, tmp)) | |
655 | return true; | |
656 | ||
657 | return false; | |
658 | } | |
659 | ||
b6814ca0 | 660 | /* Returns true if ARG is a neutral element for operation CODE |
661 | on the RIGHT side. */ | |
662 | ||
663 | static bool | |
664 | neutral_element_p (tree_code code, tree arg, bool right) | |
665 | { | |
666 | switch (code) | |
667 | { | |
668 | case PLUS_EXPR: | |
669 | case BIT_IOR_EXPR: | |
670 | case BIT_XOR_EXPR: | |
671 | return integer_zerop (arg); | |
672 | ||
673 | case LROTATE_EXPR: | |
674 | case RROTATE_EXPR: | |
675 | case LSHIFT_EXPR: | |
676 | case RSHIFT_EXPR: | |
677 | case MINUS_EXPR: | |
678 | case POINTER_PLUS_EXPR: | |
679 | return right && integer_zerop (arg); | |
680 | ||
681 | case MULT_EXPR: | |
682 | return integer_onep (arg); | |
683 | ||
684 | case TRUNC_DIV_EXPR: | |
685 | case CEIL_DIV_EXPR: | |
686 | case FLOOR_DIV_EXPR: | |
687 | case ROUND_DIV_EXPR: | |
688 | case EXACT_DIV_EXPR: | |
689 | return right && integer_onep (arg); | |
690 | ||
691 | case BIT_AND_EXPR: | |
692 | return integer_all_onesp (arg); | |
693 | ||
694 | default: | |
695 | return false; | |
696 | } | |
697 | } | |
698 | ||
699 | /* Returns true if ARG is an absorbing element for operation CODE. */ | |
700 | ||
701 | static bool | |
702 | absorbing_element_p (tree_code code, tree arg) | |
703 | { | |
704 | switch (code) | |
705 | { | |
706 | case BIT_IOR_EXPR: | |
707 | return integer_all_onesp (arg); | |
708 | ||
709 | case MULT_EXPR: | |
710 | case BIT_AND_EXPR: | |
711 | return integer_zerop (arg); | |
712 | ||
713 | default: | |
714 | return false; | |
715 | } | |
716 | } | |
717 | ||
0beac6fc | 718 | /* The function value_replacement does the main work of doing the value |
fb9912ea | 719 | replacement. Return non-zero if the replacement is done. Otherwise return |
720 | 0. If we remove the middle basic block, return 2. | |
0beac6fc | 721 | BB is the basic block where the replacement is going to be done on. ARG0 |
dac49aa5 | 722 | is argument 0 from the PHI. Likewise for ARG1. */ |
0beac6fc | 723 | |
fb9912ea | 724 | static int |
33784d89 | 725 | value_replacement (basic_block cond_bb, basic_block middle_bb, |
75a70cf9 | 726 | edge e0, edge e1, gimple phi, |
33784d89 | 727 | tree arg0, tree arg1) |
0beac6fc | 728 | { |
17b9476e | 729 | gimple_stmt_iterator gsi; |
75a70cf9 | 730 | gimple cond; |
0beac6fc | 731 | edge true_edge, false_edge; |
75a70cf9 | 732 | enum tree_code code; |
fb9912ea | 733 | bool emtpy_or_with_defined_p = true; |
0beac6fc | 734 | |
735 | /* If the type says honor signed zeros we cannot do this | |
dac49aa5 | 736 | optimization. */ |
fe994837 | 737 | if (HONOR_SIGNED_ZEROS (arg1)) |
fb9912ea | 738 | return 0; |
0beac6fc | 739 | |
fb9912ea | 740 | /* If there is a statement in MIDDLE_BB that defines one of the PHI |
741 | arguments, then adjust arg0 or arg1. */ | |
b6814ca0 | 742 | gsi = gsi_start_nondebug_after_labels_bb (middle_bb); |
fb9912ea | 743 | while (!gsi_end_p (gsi)) |
17b9476e | 744 | { |
fb9912ea | 745 | gimple stmt = gsi_stmt (gsi); |
746 | tree lhs; | |
747 | gsi_next_nondebug (&gsi); | |
748 | if (!is_gimple_assign (stmt)) | |
17b9476e | 749 | { |
fb9912ea | 750 | emtpy_or_with_defined_p = false; |
751 | continue; | |
17b9476e | 752 | } |
fb9912ea | 753 | /* Now try to adjust arg0 or arg1 according to the computation |
754 | in the statement. */ | |
755 | lhs = gimple_assign_lhs (stmt); | |
756 | if (!(lhs == arg0 | |
757 | && jump_function_from_stmt (&arg0, stmt)) | |
758 | || (lhs == arg1 | |
759 | && jump_function_from_stmt (&arg1, stmt))) | |
760 | emtpy_or_with_defined_p = false; | |
17b9476e | 761 | } |
0beac6fc | 762 | |
75a70cf9 | 763 | cond = last_stmt (cond_bb); |
764 | code = gimple_cond_code (cond); | |
0beac6fc | 765 | |
766 | /* This transformation is only valid for equality comparisons. */ | |
75a70cf9 | 767 | if (code != NE_EXPR && code != EQ_EXPR) |
fb9912ea | 768 | return 0; |
0beac6fc | 769 | |
770 | /* We need to know which is the true edge and which is the false | |
771 | edge so that we know if have abs or negative abs. */ | |
33784d89 | 772 | extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge); |
0beac6fc | 773 | |
774 | /* At this point we know we have a COND_EXPR with two successors. | |
775 | One successor is BB, the other successor is an empty block which | |
776 | falls through into BB. | |
777 | ||
778 | The condition for the COND_EXPR is known to be NE_EXPR or EQ_EXPR. | |
779 | ||
780 | There is a single PHI node at the join point (BB) with two arguments. | |
781 | ||
782 | We now need to verify that the two arguments in the PHI node match | |
783 | the two arguments to the equality comparison. */ | |
20e5647c | 784 | |
f32420fb | 785 | if (operand_equal_for_value_replacement (arg0, arg1, &code, cond)) |
0beac6fc | 786 | { |
787 | edge e; | |
788 | tree arg; | |
789 | ||
50737d20 | 790 | /* For NE_EXPR, we want to build an assignment result = arg where |
791 | arg is the PHI argument associated with the true edge. For | |
792 | EQ_EXPR we want the PHI argument associated with the false edge. */ | |
75a70cf9 | 793 | e = (code == NE_EXPR ? true_edge : false_edge); |
50737d20 | 794 | |
795 | /* Unfortunately, E may not reach BB (it may instead have gone to | |
796 | OTHER_BLOCK). If that is the case, then we want the single outgoing | |
797 | edge from OTHER_BLOCK which reaches BB and represents the desired | |
798 | path from COND_BLOCK. */ | |
33784d89 | 799 | if (e->dest == middle_bb) |
ea091dfd | 800 | e = single_succ_edge (e->dest); |
50737d20 | 801 | |
802 | /* Now we know the incoming edge to BB that has the argument for the | |
803 | RHS of our new assignment statement. */ | |
33784d89 | 804 | if (e0 == e) |
0beac6fc | 805 | arg = arg0; |
806 | else | |
807 | arg = arg1; | |
808 | ||
fb9912ea | 809 | /* If the middle basic block was empty or is defining the |
c3597b05 | 810 | PHI arguments and this is a single phi where the args are different |
811 | for the edges e0 and e1 then we can remove the middle basic block. */ | |
fb9912ea | 812 | if (emtpy_or_with_defined_p |
c3597b05 | 813 | && single_non_singleton_phi_for_edges (phi_nodes (gimple_bb (phi)), |
ce75c7c2 | 814 | e0, e1) == phi) |
fb9912ea | 815 | { |
816 | replace_phi_edge_with_variable (cond_bb, e1, phi, arg); | |
817 | /* Note that we optimized this PHI. */ | |
818 | return 2; | |
819 | } | |
820 | else | |
821 | { | |
822 | /* Replace the PHI arguments with arg. */ | |
823 | SET_PHI_ARG_DEF (phi, e0->dest_idx, arg); | |
824 | SET_PHI_ARG_DEF (phi, e1->dest_idx, arg); | |
825 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
826 | { | |
827 | fprintf (dump_file, "PHI "); | |
828 | print_generic_expr (dump_file, gimple_phi_result (phi), 0); | |
c3597b05 | 829 | fprintf (dump_file, " reduced for COND_EXPR in block %d to ", |
830 | cond_bb->index); | |
fb9912ea | 831 | print_generic_expr (dump_file, arg, 0); |
832 | fprintf (dump_file, ".\n"); | |
833 | } | |
834 | return 1; | |
835 | } | |
0beac6fc | 836 | |
0beac6fc | 837 | } |
b6814ca0 | 838 | |
839 | /* Now optimize (x != 0) ? x + y : y to just y. | |
840 | The following condition is too restrictive, there can easily be another | |
841 | stmt in middle_bb, for instance a CONVERT_EXPR for the second argument. */ | |
842 | gimple assign = last_and_only_stmt (middle_bb); | |
843 | if (!assign || gimple_code (assign) != GIMPLE_ASSIGN | |
844 | || gimple_assign_rhs_class (assign) != GIMPLE_BINARY_RHS | |
845 | || (!INTEGRAL_TYPE_P (TREE_TYPE (arg0)) | |
846 | && !POINTER_TYPE_P (TREE_TYPE (arg0)))) | |
847 | return 0; | |
848 | ||
6c96fe34 | 849 | /* Punt if there are (degenerate) PHIs in middle_bb, there should not be. */ |
850 | if (!gimple_seq_empty_p (phi_nodes (middle_bb))) | |
851 | return 0; | |
852 | ||
43fbec4a | 853 | /* Only transform if it removes the condition. */ |
854 | if (!single_non_singleton_phi_for_edges (phi_nodes (gimple_bb (phi)), e0, e1)) | |
855 | return 0; | |
856 | ||
b6814ca0 | 857 | /* Size-wise, this is always profitable. */ |
858 | if (optimize_bb_for_speed_p (cond_bb) | |
859 | /* The special case is useless if it has a low probability. */ | |
860 | && profile_status_for_fn (cfun) != PROFILE_ABSENT | |
861 | && EDGE_PRED (middle_bb, 0)->probability < PROB_EVEN | |
862 | /* If assign is cheap, there is no point avoiding it. */ | |
863 | && estimate_num_insns (assign, &eni_time_weights) | |
864 | >= 3 * estimate_num_insns (cond, &eni_time_weights)) | |
865 | return 0; | |
866 | ||
867 | tree lhs = gimple_assign_lhs (assign); | |
868 | tree rhs1 = gimple_assign_rhs1 (assign); | |
869 | tree rhs2 = gimple_assign_rhs2 (assign); | |
870 | enum tree_code code_def = gimple_assign_rhs_code (assign); | |
871 | tree cond_lhs = gimple_cond_lhs (cond); | |
872 | tree cond_rhs = gimple_cond_rhs (cond); | |
873 | ||
874 | if (((code == NE_EXPR && e1 == false_edge) | |
875 | || (code == EQ_EXPR && e1 == true_edge)) | |
876 | && arg0 == lhs | |
877 | && ((arg1 == rhs1 | |
878 | && operand_equal_for_phi_arg_p (rhs2, cond_lhs) | |
879 | && neutral_element_p (code_def, cond_rhs, true)) | |
880 | || (arg1 == rhs2 | |
881 | && operand_equal_for_phi_arg_p (rhs1, cond_lhs) | |
882 | && neutral_element_p (code_def, cond_rhs, false)) | |
883 | || (operand_equal_for_phi_arg_p (arg1, cond_rhs) | |
884 | && (operand_equal_for_phi_arg_p (rhs2, cond_lhs) | |
885 | || operand_equal_for_phi_arg_p (rhs1, cond_lhs)) | |
886 | && absorbing_element_p (code_def, cond_rhs)))) | |
887 | { | |
888 | gsi = gsi_for_stmt (cond); | |
18c06fb8 | 889 | if (INTEGRAL_TYPE_P (TREE_TYPE (lhs))) |
890 | { | |
891 | /* Moving ASSIGN might change VR of lhs, e.g. when moving u_6 | |
892 | def-stmt in: | |
893 | if (n_5 != 0) | |
894 | goto <bb 3>; | |
895 | else | |
896 | goto <bb 4>; | |
897 | ||
898 | <bb 3>: | |
899 | # RANGE [0, 4294967294] | |
900 | u_6 = n_5 + 4294967295; | |
901 | ||
902 | <bb 4>: | |
903 | # u_3 = PHI <u_6(3), 4294967295(2)> */ | |
904 | SSA_NAME_RANGE_INFO (lhs) = NULL; | |
905 | SSA_NAME_ANTI_RANGE_P (lhs) = 0; | |
906 | /* If available, we can use VR of phi result at least. */ | |
907 | tree phires = gimple_phi_result (phi); | |
908 | struct range_info_def *phires_range_info | |
909 | = SSA_NAME_RANGE_INFO (phires); | |
910 | if (phires_range_info) | |
911 | duplicate_ssa_name_range_info (lhs, SSA_NAME_RANGE_TYPE (phires), | |
912 | phires_range_info); | |
913 | } | |
b6814ca0 | 914 | gimple_stmt_iterator gsi_from = gsi_for_stmt (assign); |
915 | gsi_move_before (&gsi_from, &gsi); | |
916 | replace_phi_edge_with_variable (cond_bb, e1, phi, lhs); | |
917 | return 2; | |
918 | } | |
919 | ||
fb9912ea | 920 | return 0; |
0beac6fc | 921 | } |
922 | ||
194899bf | 923 | /* The function minmax_replacement does the main work of doing the minmax |
924 | replacement. Return true if the replacement is done. Otherwise return | |
925 | false. | |
926 | BB is the basic block where the replacement is going to be done on. ARG0 | |
927 | is argument 0 from the PHI. Likewise for ARG1. */ | |
928 | ||
929 | static bool | |
930 | minmax_replacement (basic_block cond_bb, basic_block middle_bb, | |
75a70cf9 | 931 | edge e0, edge e1, gimple phi, |
194899bf | 932 | tree arg0, tree arg1) |
933 | { | |
934 | tree result, type; | |
1a91d914 | 935 | gcond *cond; |
936 | gassign *new_stmt; | |
194899bf | 937 | edge true_edge, false_edge; |
938 | enum tree_code cmp, minmax, ass_code; | |
939 | tree smaller, larger, arg_true, arg_false; | |
75a70cf9 | 940 | gimple_stmt_iterator gsi, gsi_from; |
194899bf | 941 | |
942 | type = TREE_TYPE (PHI_RESULT (phi)); | |
943 | ||
944 | /* The optimization may be unsafe due to NaNs. */ | |
93633022 | 945 | if (HONOR_NANS (type)) |
194899bf | 946 | return false; |
947 | ||
1a91d914 | 948 | cond = as_a <gcond *> (last_stmt (cond_bb)); |
75a70cf9 | 949 | cmp = gimple_cond_code (cond); |
194899bf | 950 | |
951 | /* This transformation is only valid for order comparisons. Record which | |
952 | operand is smaller/larger if the result of the comparison is true. */ | |
953 | if (cmp == LT_EXPR || cmp == LE_EXPR) | |
954 | { | |
75a70cf9 | 955 | smaller = gimple_cond_lhs (cond); |
956 | larger = gimple_cond_rhs (cond); | |
194899bf | 957 | } |
958 | else if (cmp == GT_EXPR || cmp == GE_EXPR) | |
959 | { | |
75a70cf9 | 960 | smaller = gimple_cond_rhs (cond); |
961 | larger = gimple_cond_lhs (cond); | |
194899bf | 962 | } |
963 | else | |
964 | return false; | |
965 | ||
966 | /* We need to know which is the true edge and which is the false | |
967 | edge so that we know if have abs or negative abs. */ | |
968 | extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge); | |
969 | ||
970 | /* Forward the edges over the middle basic block. */ | |
971 | if (true_edge->dest == middle_bb) | |
972 | true_edge = EDGE_SUCC (true_edge->dest, 0); | |
973 | if (false_edge->dest == middle_bb) | |
974 | false_edge = EDGE_SUCC (false_edge->dest, 0); | |
975 | ||
976 | if (true_edge == e0) | |
977 | { | |
978 | gcc_assert (false_edge == e1); | |
979 | arg_true = arg0; | |
980 | arg_false = arg1; | |
981 | } | |
982 | else | |
983 | { | |
984 | gcc_assert (false_edge == e0); | |
985 | gcc_assert (true_edge == e1); | |
986 | arg_true = arg1; | |
987 | arg_false = arg0; | |
988 | } | |
989 | ||
990 | if (empty_block_p (middle_bb)) | |
991 | { | |
992 | if (operand_equal_for_phi_arg_p (arg_true, smaller) | |
993 | && operand_equal_for_phi_arg_p (arg_false, larger)) | |
994 | { | |
995 | /* Case | |
48e1416a | 996 | |
194899bf | 997 | if (smaller < larger) |
998 | rslt = smaller; | |
999 | else | |
1000 | rslt = larger; */ | |
1001 | minmax = MIN_EXPR; | |
1002 | } | |
1003 | else if (operand_equal_for_phi_arg_p (arg_false, smaller) | |
1004 | && operand_equal_for_phi_arg_p (arg_true, larger)) | |
1005 | minmax = MAX_EXPR; | |
1006 | else | |
1007 | return false; | |
1008 | } | |
1009 | else | |
1010 | { | |
1011 | /* Recognize the following case, assuming d <= u: | |
1012 | ||
1013 | if (a <= u) | |
1014 | b = MAX (a, d); | |
1015 | x = PHI <b, u> | |
1016 | ||
1017 | This is equivalent to | |
1018 | ||
1019 | b = MAX (a, d); | |
1020 | x = MIN (b, u); */ | |
1021 | ||
75a70cf9 | 1022 | gimple assign = last_and_only_stmt (middle_bb); |
1023 | tree lhs, op0, op1, bound; | |
194899bf | 1024 | |
1025 | if (!assign | |
75a70cf9 | 1026 | || gimple_code (assign) != GIMPLE_ASSIGN) |
194899bf | 1027 | return false; |
1028 | ||
75a70cf9 | 1029 | lhs = gimple_assign_lhs (assign); |
1030 | ass_code = gimple_assign_rhs_code (assign); | |
194899bf | 1031 | if (ass_code != MAX_EXPR && ass_code != MIN_EXPR) |
1032 | return false; | |
75a70cf9 | 1033 | op0 = gimple_assign_rhs1 (assign); |
1034 | op1 = gimple_assign_rhs2 (assign); | |
194899bf | 1035 | |
1036 | if (true_edge->src == middle_bb) | |
1037 | { | |
1038 | /* We got here if the condition is true, i.e., SMALLER < LARGER. */ | |
1039 | if (!operand_equal_for_phi_arg_p (lhs, arg_true)) | |
1040 | return false; | |
1041 | ||
1042 | if (operand_equal_for_phi_arg_p (arg_false, larger)) | |
1043 | { | |
1044 | /* Case | |
1045 | ||
1046 | if (smaller < larger) | |
1047 | { | |
1048 | r' = MAX_EXPR (smaller, bound) | |
1049 | } | |
1050 | r = PHI <r', larger> --> to be turned to MIN_EXPR. */ | |
1051 | if (ass_code != MAX_EXPR) | |
1052 | return false; | |
1053 | ||
1054 | minmax = MIN_EXPR; | |
1055 | if (operand_equal_for_phi_arg_p (op0, smaller)) | |
1056 | bound = op1; | |
1057 | else if (operand_equal_for_phi_arg_p (op1, smaller)) | |
1058 | bound = op0; | |
1059 | else | |
1060 | return false; | |
1061 | ||
1062 | /* We need BOUND <= LARGER. */ | |
49d00087 | 1063 | if (!integer_nonzerop (fold_build2 (LE_EXPR, boolean_type_node, |
1064 | bound, larger))) | |
194899bf | 1065 | return false; |
1066 | } | |
1067 | else if (operand_equal_for_phi_arg_p (arg_false, smaller)) | |
1068 | { | |
1069 | /* Case | |
1070 | ||
1071 | if (smaller < larger) | |
1072 | { | |
1073 | r' = MIN_EXPR (larger, bound) | |
1074 | } | |
1075 | r = PHI <r', smaller> --> to be turned to MAX_EXPR. */ | |
1076 | if (ass_code != MIN_EXPR) | |
1077 | return false; | |
1078 | ||
1079 | minmax = MAX_EXPR; | |
1080 | if (operand_equal_for_phi_arg_p (op0, larger)) | |
1081 | bound = op1; | |
1082 | else if (operand_equal_for_phi_arg_p (op1, larger)) | |
1083 | bound = op0; | |
1084 | else | |
1085 | return false; | |
1086 | ||
1087 | /* We need BOUND >= SMALLER. */ | |
49d00087 | 1088 | if (!integer_nonzerop (fold_build2 (GE_EXPR, boolean_type_node, |
1089 | bound, smaller))) | |
194899bf | 1090 | return false; |
1091 | } | |
1092 | else | |
1093 | return false; | |
1094 | } | |
1095 | else | |
1096 | { | |
1097 | /* We got here if the condition is false, i.e., SMALLER > LARGER. */ | |
1098 | if (!operand_equal_for_phi_arg_p (lhs, arg_false)) | |
1099 | return false; | |
1100 | ||
1101 | if (operand_equal_for_phi_arg_p (arg_true, larger)) | |
1102 | { | |
1103 | /* Case | |
1104 | ||
1105 | if (smaller > larger) | |
1106 | { | |
1107 | r' = MIN_EXPR (smaller, bound) | |
1108 | } | |
1109 | r = PHI <r', larger> --> to be turned to MAX_EXPR. */ | |
1110 | if (ass_code != MIN_EXPR) | |
1111 | return false; | |
1112 | ||
1113 | minmax = MAX_EXPR; | |
1114 | if (operand_equal_for_phi_arg_p (op0, smaller)) | |
1115 | bound = op1; | |
1116 | else if (operand_equal_for_phi_arg_p (op1, smaller)) | |
1117 | bound = op0; | |
1118 | else | |
1119 | return false; | |
1120 | ||
1121 | /* We need BOUND >= LARGER. */ | |
49d00087 | 1122 | if (!integer_nonzerop (fold_build2 (GE_EXPR, boolean_type_node, |
1123 | bound, larger))) | |
194899bf | 1124 | return false; |
1125 | } | |
1126 | else if (operand_equal_for_phi_arg_p (arg_true, smaller)) | |
1127 | { | |
1128 | /* Case | |
1129 | ||
1130 | if (smaller > larger) | |
1131 | { | |
1132 | r' = MAX_EXPR (larger, bound) | |
1133 | } | |
1134 | r = PHI <r', smaller> --> to be turned to MIN_EXPR. */ | |
1135 | if (ass_code != MAX_EXPR) | |
1136 | return false; | |
1137 | ||
1138 | minmax = MIN_EXPR; | |
1139 | if (operand_equal_for_phi_arg_p (op0, larger)) | |
1140 | bound = op1; | |
1141 | else if (operand_equal_for_phi_arg_p (op1, larger)) | |
1142 | bound = op0; | |
1143 | else | |
1144 | return false; | |
1145 | ||
1146 | /* We need BOUND <= SMALLER. */ | |
49d00087 | 1147 | if (!integer_nonzerop (fold_build2 (LE_EXPR, boolean_type_node, |
1148 | bound, smaller))) | |
194899bf | 1149 | return false; |
1150 | } | |
1151 | else | |
1152 | return false; | |
1153 | } | |
1154 | ||
1155 | /* Move the statement from the middle block. */ | |
75a70cf9 | 1156 | gsi = gsi_last_bb (cond_bb); |
445a6ba5 | 1157 | gsi_from = gsi_last_nondebug_bb (middle_bb); |
75a70cf9 | 1158 | gsi_move_before (&gsi_from, &gsi); |
194899bf | 1159 | } |
1160 | ||
1161 | /* Emit the statement to compute min/max. */ | |
1162 | result = duplicate_ssa_name (PHI_RESULT (phi), NULL); | |
e9cf809e | 1163 | new_stmt = gimple_build_assign (result, minmax, arg0, arg1); |
75a70cf9 | 1164 | gsi = gsi_last_bb (cond_bb); |
1165 | gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT); | |
194899bf | 1166 | |
a4844041 | 1167 | replace_phi_edge_with_variable (cond_bb, e1, phi, result); |
194899bf | 1168 | return true; |
1169 | } | |
1170 | ||
70512b93 | 1171 | /* The function absolute_replacement does the main work of doing the absolute |
1172 | replacement. Return true if the replacement is done. Otherwise return | |
1173 | false. | |
1174 | bb is the basic block where the replacement is going to be done on. arg0 | |
f7f07c95 | 1175 | is argument 0 from the phi. Likewise for arg1. */ |
33784d89 | 1176 | |
70512b93 | 1177 | static bool |
33784d89 | 1178 | abs_replacement (basic_block cond_bb, basic_block middle_bb, |
a4844041 | 1179 | edge e0 ATTRIBUTE_UNUSED, edge e1, |
75a70cf9 | 1180 | gimple phi, tree arg0, tree arg1) |
70512b93 | 1181 | { |
1182 | tree result; | |
1a91d914 | 1183 | gassign *new_stmt; |
1184 | gimple cond; | |
75a70cf9 | 1185 | gimple_stmt_iterator gsi; |
70512b93 | 1186 | edge true_edge, false_edge; |
75a70cf9 | 1187 | gimple assign; |
70512b93 | 1188 | edge e; |
194899bf | 1189 | tree rhs, lhs; |
70512b93 | 1190 | bool negate; |
1191 | enum tree_code cond_code; | |
1192 | ||
1193 | /* If the type says honor signed zeros we cannot do this | |
dac49aa5 | 1194 | optimization. */ |
fe994837 | 1195 | if (HONOR_SIGNED_ZEROS (arg1)) |
70512b93 | 1196 | return false; |
1197 | ||
70512b93 | 1198 | /* OTHER_BLOCK must have only one executable statement which must have the |
1199 | form arg0 = -arg1 or arg1 = -arg0. */ | |
70512b93 | 1200 | |
194899bf | 1201 | assign = last_and_only_stmt (middle_bb); |
70512b93 | 1202 | /* If we did not find the proper negation assignment, then we can not |
1203 | optimize. */ | |
1204 | if (assign == NULL) | |
1205 | return false; | |
48e1416a | 1206 | |
194899bf | 1207 | /* If we got here, then we have found the only executable statement |
1208 | in OTHER_BLOCK. If it is anything other than arg = -arg1 or | |
1209 | arg1 = -arg0, then we can not optimize. */ | |
75a70cf9 | 1210 | if (gimple_code (assign) != GIMPLE_ASSIGN) |
194899bf | 1211 | return false; |
1212 | ||
75a70cf9 | 1213 | lhs = gimple_assign_lhs (assign); |
194899bf | 1214 | |
75a70cf9 | 1215 | if (gimple_assign_rhs_code (assign) != NEGATE_EXPR) |
194899bf | 1216 | return false; |
1217 | ||
75a70cf9 | 1218 | rhs = gimple_assign_rhs1 (assign); |
48e1416a | 1219 | |
194899bf | 1220 | /* The assignment has to be arg0 = -arg1 or arg1 = -arg0. */ |
1221 | if (!(lhs == arg0 && rhs == arg1) | |
1222 | && !(lhs == arg1 && rhs == arg0)) | |
1223 | return false; | |
70512b93 | 1224 | |
75a70cf9 | 1225 | cond = last_stmt (cond_bb); |
70512b93 | 1226 | result = PHI_RESULT (phi); |
1227 | ||
1228 | /* Only relationals comparing arg[01] against zero are interesting. */ | |
75a70cf9 | 1229 | cond_code = gimple_cond_code (cond); |
70512b93 | 1230 | if (cond_code != GT_EXPR && cond_code != GE_EXPR |
1231 | && cond_code != LT_EXPR && cond_code != LE_EXPR) | |
1232 | return false; | |
1233 | ||
dac49aa5 | 1234 | /* Make sure the conditional is arg[01] OP y. */ |
75a70cf9 | 1235 | if (gimple_cond_lhs (cond) != rhs) |
70512b93 | 1236 | return false; |
1237 | ||
75a70cf9 | 1238 | if (FLOAT_TYPE_P (TREE_TYPE (gimple_cond_rhs (cond))) |
1239 | ? real_zerop (gimple_cond_rhs (cond)) | |
1240 | : integer_zerop (gimple_cond_rhs (cond))) | |
70512b93 | 1241 | ; |
1242 | else | |
1243 | return false; | |
1244 | ||
1245 | /* We need to know which is the true edge and which is the false | |
1246 | edge so that we know if have abs or negative abs. */ | |
33784d89 | 1247 | extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge); |
70512b93 | 1248 | |
1249 | /* For GT_EXPR/GE_EXPR, if the true edge goes to OTHER_BLOCK, then we | |
1250 | will need to negate the result. Similarly for LT_EXPR/LE_EXPR if | |
1251 | the false edge goes to OTHER_BLOCK. */ | |
1252 | if (cond_code == GT_EXPR || cond_code == GE_EXPR) | |
1253 | e = true_edge; | |
1254 | else | |
1255 | e = false_edge; | |
20e5647c | 1256 | |
33784d89 | 1257 | if (e->dest == middle_bb) |
70512b93 | 1258 | negate = true; |
1259 | else | |
1260 | negate = false; | |
20e5647c | 1261 | |
33784d89 | 1262 | result = duplicate_ssa_name (result, NULL); |
20e5647c | 1263 | |
70512b93 | 1264 | if (negate) |
f9e245b2 | 1265 | lhs = make_ssa_name (TREE_TYPE (result)); |
70512b93 | 1266 | else |
1267 | lhs = result; | |
1268 | ||
dac49aa5 | 1269 | /* Build the modify expression with abs expression. */ |
e9cf809e | 1270 | new_stmt = gimple_build_assign (lhs, ABS_EXPR, rhs); |
70512b93 | 1271 | |
75a70cf9 | 1272 | gsi = gsi_last_bb (cond_bb); |
1273 | gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT); | |
70512b93 | 1274 | |
1275 | if (negate) | |
1276 | { | |
75a70cf9 | 1277 | /* Get the right GSI. We want to insert after the recently |
70512b93 | 1278 | added ABS_EXPR statement (which we know is the first statement |
1279 | in the block. */ | |
e9cf809e | 1280 | new_stmt = gimple_build_assign (result, NEGATE_EXPR, lhs); |
70512b93 | 1281 | |
75a70cf9 | 1282 | gsi_insert_after (&gsi, new_stmt, GSI_NEW_STMT); |
70512b93 | 1283 | } |
20e5647c | 1284 | |
a4844041 | 1285 | replace_phi_edge_with_variable (cond_bb, e1, phi, result); |
70512b93 | 1286 | |
1287 | /* Note that we optimized this PHI. */ | |
1288 | return true; | |
1289 | } | |
1290 | ||
e6d0e152 | 1291 | /* Auxiliary functions to determine the set of memory accesses which |
1292 | can't trap because they are preceded by accesses to the same memory | |
182cf5a9 | 1293 | portion. We do that for MEM_REFs, so we only need to track |
e6d0e152 | 1294 | the SSA_NAME of the pointer indirectly referenced. The algorithm |
1295 | simply is a walk over all instructions in dominator order. When | |
182cf5a9 | 1296 | we see an MEM_REF we determine if we've already seen a same |
e6d0e152 | 1297 | ref anywhere up to the root of the dominator tree. If we do the |
af4f74fa | 1298 | current access can't trap. If we don't see any dominating access |
e6d0e152 | 1299 | the current access might trap, but might also make later accesses |
af4f74fa | 1300 | non-trapping, so we remember it. We need to be careful with loads |
1301 | or stores, for instance a load might not trap, while a store would, | |
1302 | so if we see a dominating read access this doesn't mean that a later | |
1303 | write access would not trap. Hence we also need to differentiate the | |
1304 | type of access(es) seen. | |
1305 | ||
1306 | ??? We currently are very conservative and assume that a load might | |
1307 | trap even if a store doesn't (write-only memory). This probably is | |
1308 | overly conservative. */ | |
e6d0e152 | 1309 | |
182cf5a9 | 1310 | /* A hash-table of SSA_NAMEs, and in which basic block an MEM_REF |
e6d0e152 | 1311 | through it was seen, which would constitute a no-trap region for |
1312 | same accesses. */ | |
1313 | struct name_to_bb | |
1314 | { | |
963aee26 | 1315 | unsigned int ssa_name_ver; |
42540642 | 1316 | unsigned int phase; |
963aee26 | 1317 | bool store; |
1318 | HOST_WIDE_INT offset, size; | |
e6d0e152 | 1319 | basic_block bb; |
1320 | }; | |
1321 | ||
d9dd21a8 | 1322 | /* Hashtable helpers. */ |
1323 | ||
1324 | struct ssa_names_hasher : typed_free_remove <name_to_bb> | |
1325 | { | |
9969c043 | 1326 | typedef name_to_bb *value_type; |
1327 | typedef name_to_bb *compare_type; | |
1328 | static inline hashval_t hash (const name_to_bb *); | |
1329 | static inline bool equal (const name_to_bb *, const name_to_bb *); | |
d9dd21a8 | 1330 | }; |
e6d0e152 | 1331 | |
42540642 | 1332 | /* Used for quick clearing of the hash-table when we see calls. |
1333 | Hash entries with phase < nt_call_phase are invalid. */ | |
1334 | static unsigned int nt_call_phase; | |
1335 | ||
963aee26 | 1336 | /* The hash function. */ |
d9dd21a8 | 1337 | |
1338 | inline hashval_t | |
9969c043 | 1339 | ssa_names_hasher::hash (const name_to_bb *n) |
e6d0e152 | 1340 | { |
963aee26 | 1341 | return n->ssa_name_ver ^ (((hashval_t) n->store) << 31) |
1342 | ^ (n->offset << 6) ^ (n->size << 3); | |
e6d0e152 | 1343 | } |
1344 | ||
963aee26 | 1345 | /* The equality function of *P1 and *P2. */ |
e6d0e152 | 1346 | |
d9dd21a8 | 1347 | inline bool |
9969c043 | 1348 | ssa_names_hasher::equal (const name_to_bb *n1, const name_to_bb *n2) |
d9dd21a8 | 1349 | { |
963aee26 | 1350 | return n1->ssa_name_ver == n2->ssa_name_ver |
1351 | && n1->store == n2->store | |
1352 | && n1->offset == n2->offset | |
1353 | && n1->size == n2->size; | |
e6d0e152 | 1354 | } |
1355 | ||
c1f445d2 | 1356 | class nontrapping_dom_walker : public dom_walker |
1357 | { | |
1358 | public: | |
431205b7 | 1359 | nontrapping_dom_walker (cdi_direction direction, hash_set<tree> *ps) |
c1f445d2 | 1360 | : dom_walker (direction), m_nontrapping (ps), m_seen_ssa_names (128) {} |
1361 | ||
1362 | virtual void before_dom_children (basic_block); | |
1363 | virtual void after_dom_children (basic_block); | |
1364 | ||
1365 | private: | |
1366 | ||
1367 | /* We see the expression EXP in basic block BB. If it's an interesting | |
1368 | expression (an MEM_REF through an SSA_NAME) possibly insert the | |
1369 | expression into the set NONTRAP or the hash table of seen expressions. | |
1370 | STORE is true if this expression is on the LHS, otherwise it's on | |
1371 | the RHS. */ | |
1372 | void add_or_mark_expr (basic_block, tree, bool); | |
1373 | ||
431205b7 | 1374 | hash_set<tree> *m_nontrapping; |
c1f445d2 | 1375 | |
1376 | /* The hash table for remembering what we've seen. */ | |
1377 | hash_table<ssa_names_hasher> m_seen_ssa_names; | |
1378 | }; | |
1379 | ||
1380 | /* Called by walk_dominator_tree, when entering the block BB. */ | |
1381 | void | |
1382 | nontrapping_dom_walker::before_dom_children (basic_block bb) | |
1383 | { | |
1384 | edge e; | |
1385 | edge_iterator ei; | |
1386 | gimple_stmt_iterator gsi; | |
1387 | ||
1388 | /* If we haven't seen all our predecessors, clear the hash-table. */ | |
1389 | FOR_EACH_EDGE (e, ei, bb->preds) | |
1390 | if ((((size_t)e->src->aux) & 2) == 0) | |
1391 | { | |
1392 | nt_call_phase++; | |
1393 | break; | |
1394 | } | |
1395 | ||
1396 | /* Mark this BB as being on the path to dominator root and as visited. */ | |
1397 | bb->aux = (void*)(1 | 2); | |
1398 | ||
1399 | /* And walk the statements in order. */ | |
1400 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
1401 | { | |
1402 | gimple stmt = gsi_stmt (gsi); | |
1403 | ||
1404 | if (is_gimple_call (stmt) && !nonfreeing_call_p (stmt)) | |
1405 | nt_call_phase++; | |
1406 | else if (gimple_assign_single_p (stmt) && !gimple_has_volatile_ops (stmt)) | |
1407 | { | |
1408 | add_or_mark_expr (bb, gimple_assign_lhs (stmt), true); | |
1409 | add_or_mark_expr (bb, gimple_assign_rhs1 (stmt), false); | |
1410 | } | |
1411 | } | |
1412 | } | |
1413 | ||
1414 | /* Called by walk_dominator_tree, when basic block BB is exited. */ | |
1415 | void | |
1416 | nontrapping_dom_walker::after_dom_children (basic_block bb) | |
1417 | { | |
1418 | /* This BB isn't on the path to dominator root anymore. */ | |
1419 | bb->aux = (void*)2; | |
1420 | } | |
d9dd21a8 | 1421 | |
f0b5f617 | 1422 | /* We see the expression EXP in basic block BB. If it's an interesting |
182cf5a9 | 1423 | expression (an MEM_REF through an SSA_NAME) possibly insert the |
af4f74fa | 1424 | expression into the set NONTRAP or the hash table of seen expressions. |
1425 | STORE is true if this expression is on the LHS, otherwise it's on | |
1426 | the RHS. */ | |
c1f445d2 | 1427 | void |
1428 | nontrapping_dom_walker::add_or_mark_expr (basic_block bb, tree exp, bool store) | |
e6d0e152 | 1429 | { |
963aee26 | 1430 | HOST_WIDE_INT size; |
1431 | ||
182cf5a9 | 1432 | if (TREE_CODE (exp) == MEM_REF |
963aee26 | 1433 | && TREE_CODE (TREE_OPERAND (exp, 0)) == SSA_NAME |
e913b5cd | 1434 | && tree_fits_shwi_p (TREE_OPERAND (exp, 1)) |
963aee26 | 1435 | && (size = int_size_in_bytes (TREE_TYPE (exp))) > 0) |
e6d0e152 | 1436 | { |
1437 | tree name = TREE_OPERAND (exp, 0); | |
1438 | struct name_to_bb map; | |
d9dd21a8 | 1439 | name_to_bb **slot; |
af4f74fa | 1440 | struct name_to_bb *n2bb; |
e6d0e152 | 1441 | basic_block found_bb = 0; |
1442 | ||
182cf5a9 | 1443 | /* Try to find the last seen MEM_REF through the same |
e6d0e152 | 1444 | SSA_NAME, which can trap. */ |
963aee26 | 1445 | map.ssa_name_ver = SSA_NAME_VERSION (name); |
42540642 | 1446 | map.phase = 0; |
e6d0e152 | 1447 | map.bb = 0; |
af4f74fa | 1448 | map.store = store; |
e913b5cd | 1449 | map.offset = tree_to_shwi (TREE_OPERAND (exp, 1)); |
963aee26 | 1450 | map.size = size; |
1451 | ||
c1f445d2 | 1452 | slot = m_seen_ssa_names.find_slot (&map, INSERT); |
d9dd21a8 | 1453 | n2bb = *slot; |
42540642 | 1454 | if (n2bb && n2bb->phase >= nt_call_phase) |
af4f74fa | 1455 | found_bb = n2bb->bb; |
e6d0e152 | 1456 | |
182cf5a9 | 1457 | /* If we've found a trapping MEM_REF, _and_ it dominates EXP |
e6d0e152 | 1458 | (it's in a basic block on the path from us to the dominator root) |
1459 | then we can't trap. */ | |
42540642 | 1460 | if (found_bb && (((size_t)found_bb->aux) & 1) == 1) |
e6d0e152 | 1461 | { |
431205b7 | 1462 | m_nontrapping->add (exp); |
e6d0e152 | 1463 | } |
1464 | else | |
1465 | { | |
1466 | /* EXP might trap, so insert it into the hash table. */ | |
af4f74fa | 1467 | if (n2bb) |
e6d0e152 | 1468 | { |
42540642 | 1469 | n2bb->phase = nt_call_phase; |
af4f74fa | 1470 | n2bb->bb = bb; |
e6d0e152 | 1471 | } |
1472 | else | |
1473 | { | |
af4f74fa | 1474 | n2bb = XNEW (struct name_to_bb); |
963aee26 | 1475 | n2bb->ssa_name_ver = SSA_NAME_VERSION (name); |
42540642 | 1476 | n2bb->phase = nt_call_phase; |
af4f74fa | 1477 | n2bb->bb = bb; |
1478 | n2bb->store = store; | |
963aee26 | 1479 | n2bb->offset = map.offset; |
1480 | n2bb->size = size; | |
af4f74fa | 1481 | *slot = n2bb; |
e6d0e152 | 1482 | } |
1483 | } | |
1484 | } | |
1485 | } | |
1486 | ||
e6d0e152 | 1487 | /* This is the entry point of gathering non trapping memory accesses. |
1488 | It will do a dominator walk over the whole function, and it will | |
1489 | make use of the bb->aux pointers. It returns a set of trees | |
182cf5a9 | 1490 | (the MEM_REFs itself) which can't trap. */ |
431205b7 | 1491 | static hash_set<tree> * |
e6d0e152 | 1492 | get_non_trapping (void) |
1493 | { | |
42540642 | 1494 | nt_call_phase = 0; |
431205b7 | 1495 | hash_set<tree> *nontrap = new hash_set<tree>; |
e6d0e152 | 1496 | /* We're going to do a dominator walk, so ensure that we have |
1497 | dominance information. */ | |
1498 | calculate_dominance_info (CDI_DOMINATORS); | |
1499 | ||
54c91640 | 1500 | nontrapping_dom_walker (CDI_DOMINATORS, nontrap) |
1501 | .walk (cfun->cfg->x_entry_block_ptr); | |
1502 | ||
42540642 | 1503 | clear_aux_for_blocks (); |
e6d0e152 | 1504 | return nontrap; |
1505 | } | |
1506 | ||
1507 | /* Do the main work of conditional store replacement. We already know | |
1508 | that the recognized pattern looks like so: | |
1509 | ||
1510 | split: | |
1511 | if (cond) goto MIDDLE_BB; else goto JOIN_BB (edge E1) | |
1512 | MIDDLE_BB: | |
1513 | something | |
1514 | fallthrough (edge E0) | |
1515 | JOIN_BB: | |
1516 | some more | |
1517 | ||
1518 | We check that MIDDLE_BB contains only one store, that that store | |
1519 | doesn't trap (not via NOTRAP, but via checking if an access to the same | |
1520 | memory location dominates us) and that the store has a "simple" RHS. */ | |
1521 | ||
1522 | static bool | |
1523 | cond_store_replacement (basic_block middle_bb, basic_block join_bb, | |
431205b7 | 1524 | edge e0, edge e1, hash_set<tree> *nontrap) |
e6d0e152 | 1525 | { |
75a70cf9 | 1526 | gimple assign = last_and_only_stmt (middle_bb); |
03d37e4e | 1527 | tree lhs, rhs, name, name2; |
1a91d914 | 1528 | gphi *newphi; |
1529 | gassign *new_stmt; | |
75a70cf9 | 1530 | gimple_stmt_iterator gsi; |
efbcb6de | 1531 | source_location locus; |
e6d0e152 | 1532 | |
1533 | /* Check if middle_bb contains of only one store. */ | |
1534 | if (!assign | |
6cc085b6 | 1535 | || !gimple_assign_single_p (assign) |
1536 | || gimple_has_volatile_ops (assign)) | |
e6d0e152 | 1537 | return false; |
1538 | ||
efbcb6de | 1539 | locus = gimple_location (assign); |
75a70cf9 | 1540 | lhs = gimple_assign_lhs (assign); |
1541 | rhs = gimple_assign_rhs1 (assign); | |
182cf5a9 | 1542 | if (TREE_CODE (lhs) != MEM_REF |
91cf53d5 | 1543 | || TREE_CODE (TREE_OPERAND (lhs, 0)) != SSA_NAME |
3211fa0a | 1544 | || !is_gimple_reg_type (TREE_TYPE (lhs))) |
e6d0e152 | 1545 | return false; |
91cf53d5 | 1546 | |
e6d0e152 | 1547 | /* Prove that we can move the store down. We could also check |
1548 | TREE_THIS_NOTRAP here, but in that case we also could move stores, | |
1549 | whose value is not available readily, which we want to avoid. */ | |
431205b7 | 1550 | if (!nontrap->contains (lhs)) |
e6d0e152 | 1551 | return false; |
1552 | ||
1553 | /* Now we've checked the constraints, so do the transformation: | |
1554 | 1) Remove the single store. */ | |
75a70cf9 | 1555 | gsi = gsi_for_stmt (assign); |
3211fa0a | 1556 | unlink_stmt_vdef (assign); |
75a70cf9 | 1557 | gsi_remove (&gsi, true); |
91cf53d5 | 1558 | release_defs (assign); |
e6d0e152 | 1559 | |
03d37e4e | 1560 | /* 2) Insert a load from the memory of the store to the temporary |
e6d0e152 | 1561 | on the edge which did not contain the store. */ |
1562 | lhs = unshare_expr (lhs); | |
03d37e4e | 1563 | name = make_temp_ssa_name (TREE_TYPE (lhs), NULL, "cstore"); |
1564 | new_stmt = gimple_build_assign (name, lhs); | |
efbcb6de | 1565 | gimple_set_location (new_stmt, locus); |
75a70cf9 | 1566 | gsi_insert_on_edge (e1, new_stmt); |
e6d0e152 | 1567 | |
03d37e4e | 1568 | /* 3) Create a PHI node at the join block, with one argument |
e6d0e152 | 1569 | holding the old RHS, and the other holding the temporary |
1570 | where we stored the old memory contents. */ | |
03d37e4e | 1571 | name2 = make_temp_ssa_name (TREE_TYPE (lhs), NULL, "cstore"); |
1572 | newphi = create_phi_node (name2, join_bb); | |
60d535d2 | 1573 | add_phi_arg (newphi, rhs, e0, locus); |
1574 | add_phi_arg (newphi, name, e1, locus); | |
e6d0e152 | 1575 | |
1576 | lhs = unshare_expr (lhs); | |
75a70cf9 | 1577 | new_stmt = gimple_build_assign (lhs, PHI_RESULT (newphi)); |
e6d0e152 | 1578 | |
03d37e4e | 1579 | /* 4) Insert that PHI node. */ |
75a70cf9 | 1580 | gsi = gsi_after_labels (join_bb); |
1581 | if (gsi_end_p (gsi)) | |
e6d0e152 | 1582 | { |
75a70cf9 | 1583 | gsi = gsi_last_bb (join_bb); |
1584 | gsi_insert_after (&gsi, new_stmt, GSI_NEW_STMT); | |
e6d0e152 | 1585 | } |
1586 | else | |
75a70cf9 | 1587 | gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT); |
e6d0e152 | 1588 | |
1589 | return true; | |
1590 | } | |
4ee9c684 | 1591 | |
ec611e12 | 1592 | /* Do the main work of conditional store replacement. */ |
91cf53d5 | 1593 | |
1594 | static bool | |
ec611e12 | 1595 | cond_if_else_store_replacement_1 (basic_block then_bb, basic_block else_bb, |
1596 | basic_block join_bb, gimple then_assign, | |
1597 | gimple else_assign) | |
91cf53d5 | 1598 | { |
03d37e4e | 1599 | tree lhs_base, lhs, then_rhs, else_rhs, name; |
91cf53d5 | 1600 | source_location then_locus, else_locus; |
1601 | gimple_stmt_iterator gsi; | |
1a91d914 | 1602 | gphi *newphi; |
1603 | gassign *new_stmt; | |
91cf53d5 | 1604 | |
91cf53d5 | 1605 | if (then_assign == NULL |
1606 | || !gimple_assign_single_p (then_assign) | |
3c25489e | 1607 | || gimple_clobber_p (then_assign) |
6cc085b6 | 1608 | || gimple_has_volatile_ops (then_assign) |
91cf53d5 | 1609 | || else_assign == NULL |
3c25489e | 1610 | || !gimple_assign_single_p (else_assign) |
6cc085b6 | 1611 | || gimple_clobber_p (else_assign) |
1612 | || gimple_has_volatile_ops (else_assign)) | |
91cf53d5 | 1613 | return false; |
1614 | ||
1615 | lhs = gimple_assign_lhs (then_assign); | |
1616 | if (!is_gimple_reg_type (TREE_TYPE (lhs)) | |
1617 | || !operand_equal_p (lhs, gimple_assign_lhs (else_assign), 0)) | |
1618 | return false; | |
1619 | ||
1620 | lhs_base = get_base_address (lhs); | |
1621 | if (lhs_base == NULL_TREE | |
1622 | || (!DECL_P (lhs_base) && TREE_CODE (lhs_base) != MEM_REF)) | |
1623 | return false; | |
1624 | ||
1625 | then_rhs = gimple_assign_rhs1 (then_assign); | |
1626 | else_rhs = gimple_assign_rhs1 (else_assign); | |
1627 | then_locus = gimple_location (then_assign); | |
1628 | else_locus = gimple_location (else_assign); | |
1629 | ||
1630 | /* Now we've checked the constraints, so do the transformation: | |
1631 | 1) Remove the stores. */ | |
1632 | gsi = gsi_for_stmt (then_assign); | |
1633 | unlink_stmt_vdef (then_assign); | |
1634 | gsi_remove (&gsi, true); | |
1635 | release_defs (then_assign); | |
1636 | ||
1637 | gsi = gsi_for_stmt (else_assign); | |
1638 | unlink_stmt_vdef (else_assign); | |
1639 | gsi_remove (&gsi, true); | |
1640 | release_defs (else_assign); | |
1641 | ||
03d37e4e | 1642 | /* 2) Create a PHI node at the join block, with one argument |
91cf53d5 | 1643 | holding the old RHS, and the other holding the temporary |
1644 | where we stored the old memory contents. */ | |
03d37e4e | 1645 | name = make_temp_ssa_name (TREE_TYPE (lhs), NULL, "cstore"); |
1646 | newphi = create_phi_node (name, join_bb); | |
60d535d2 | 1647 | add_phi_arg (newphi, then_rhs, EDGE_SUCC (then_bb, 0), then_locus); |
1648 | add_phi_arg (newphi, else_rhs, EDGE_SUCC (else_bb, 0), else_locus); | |
91cf53d5 | 1649 | |
1650 | new_stmt = gimple_build_assign (lhs, PHI_RESULT (newphi)); | |
1651 | ||
03d37e4e | 1652 | /* 3) Insert that PHI node. */ |
91cf53d5 | 1653 | gsi = gsi_after_labels (join_bb); |
1654 | if (gsi_end_p (gsi)) | |
1655 | { | |
1656 | gsi = gsi_last_bb (join_bb); | |
1657 | gsi_insert_after (&gsi, new_stmt, GSI_NEW_STMT); | |
1658 | } | |
1659 | else | |
1660 | gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT); | |
1661 | ||
1662 | return true; | |
1663 | } | |
1664 | ||
ec611e12 | 1665 | /* Conditional store replacement. We already know |
1666 | that the recognized pattern looks like so: | |
1667 | ||
1668 | split: | |
1669 | if (cond) goto THEN_BB; else goto ELSE_BB (edge E1) | |
1670 | THEN_BB: | |
1671 | ... | |
1672 | X = Y; | |
1673 | ... | |
1674 | goto JOIN_BB; | |
1675 | ELSE_BB: | |
1676 | ... | |
1677 | X = Z; | |
1678 | ... | |
1679 | fallthrough (edge E0) | |
1680 | JOIN_BB: | |
1681 | some more | |
1682 | ||
1683 | We check that it is safe to sink the store to JOIN_BB by verifying that | |
1684 | there are no read-after-write or write-after-write dependencies in | |
1685 | THEN_BB and ELSE_BB. */ | |
1686 | ||
1687 | static bool | |
1688 | cond_if_else_store_replacement (basic_block then_bb, basic_block else_bb, | |
1689 | basic_block join_bb) | |
1690 | { | |
1691 | gimple then_assign = last_and_only_stmt (then_bb); | |
1692 | gimple else_assign = last_and_only_stmt (else_bb); | |
f1f41a6c | 1693 | vec<data_reference_p> then_datarefs, else_datarefs; |
1694 | vec<ddr_p> then_ddrs, else_ddrs; | |
ec611e12 | 1695 | gimple then_store, else_store; |
1696 | bool found, ok = false, res; | |
1697 | struct data_dependence_relation *ddr; | |
1698 | data_reference_p then_dr, else_dr; | |
1699 | int i, j; | |
1700 | tree then_lhs, else_lhs; | |
ec611e12 | 1701 | basic_block blocks[3]; |
1702 | ||
1703 | if (MAX_STORES_TO_SINK == 0) | |
1704 | return false; | |
1705 | ||
1706 | /* Handle the case with single statement in THEN_BB and ELSE_BB. */ | |
1707 | if (then_assign && else_assign) | |
1708 | return cond_if_else_store_replacement_1 (then_bb, else_bb, join_bb, | |
1709 | then_assign, else_assign); | |
1710 | ||
1711 | /* Find data references. */ | |
f1f41a6c | 1712 | then_datarefs.create (1); |
1713 | else_datarefs.create (1); | |
ec611e12 | 1714 | if ((find_data_references_in_bb (NULL, then_bb, &then_datarefs) |
1715 | == chrec_dont_know) | |
f1f41a6c | 1716 | || !then_datarefs.length () |
ec611e12 | 1717 | || (find_data_references_in_bb (NULL, else_bb, &else_datarefs) |
c71d3c24 | 1718 | == chrec_dont_know) |
f1f41a6c | 1719 | || !else_datarefs.length ()) |
ec611e12 | 1720 | { |
1721 | free_data_refs (then_datarefs); | |
1722 | free_data_refs (else_datarefs); | |
1723 | return false; | |
1724 | } | |
1725 | ||
1726 | /* Find pairs of stores with equal LHS. */ | |
4997014d | 1727 | auto_vec<gimple, 1> then_stores, else_stores; |
f1f41a6c | 1728 | FOR_EACH_VEC_ELT (then_datarefs, i, then_dr) |
ec611e12 | 1729 | { |
1730 | if (DR_IS_READ (then_dr)) | |
1731 | continue; | |
1732 | ||
1733 | then_store = DR_STMT (then_dr); | |
728dcc71 | 1734 | then_lhs = gimple_get_lhs (then_store); |
c71d3c24 | 1735 | if (then_lhs == NULL_TREE) |
1736 | continue; | |
ec611e12 | 1737 | found = false; |
1738 | ||
f1f41a6c | 1739 | FOR_EACH_VEC_ELT (else_datarefs, j, else_dr) |
ec611e12 | 1740 | { |
1741 | if (DR_IS_READ (else_dr)) | |
1742 | continue; | |
1743 | ||
1744 | else_store = DR_STMT (else_dr); | |
728dcc71 | 1745 | else_lhs = gimple_get_lhs (else_store); |
c71d3c24 | 1746 | if (else_lhs == NULL_TREE) |
1747 | continue; | |
ec611e12 | 1748 | |
1749 | if (operand_equal_p (then_lhs, else_lhs, 0)) | |
1750 | { | |
1751 | found = true; | |
1752 | break; | |
1753 | } | |
1754 | } | |
1755 | ||
1756 | if (!found) | |
1757 | continue; | |
1758 | ||
f1f41a6c | 1759 | then_stores.safe_push (then_store); |
1760 | else_stores.safe_push (else_store); | |
ec611e12 | 1761 | } |
1762 | ||
1763 | /* No pairs of stores found. */ | |
f1f41a6c | 1764 | if (!then_stores.length () |
1765 | || then_stores.length () > (unsigned) MAX_STORES_TO_SINK) | |
ec611e12 | 1766 | { |
1767 | free_data_refs (then_datarefs); | |
1768 | free_data_refs (else_datarefs); | |
ec611e12 | 1769 | return false; |
1770 | } | |
1771 | ||
1772 | /* Compute and check data dependencies in both basic blocks. */ | |
f1f41a6c | 1773 | then_ddrs.create (1); |
1774 | else_ddrs.create (1); | |
1775 | if (!compute_all_dependences (then_datarefs, &then_ddrs, | |
1e094109 | 1776 | vNULL, false) |
f1f41a6c | 1777 | || !compute_all_dependences (else_datarefs, &else_ddrs, |
1e094109 | 1778 | vNULL, false)) |
8b3fb720 | 1779 | { |
1780 | free_dependence_relations (then_ddrs); | |
1781 | free_dependence_relations (else_ddrs); | |
1782 | free_data_refs (then_datarefs); | |
1783 | free_data_refs (else_datarefs); | |
8b3fb720 | 1784 | return false; |
1785 | } | |
ec611e12 | 1786 | blocks[0] = then_bb; |
1787 | blocks[1] = else_bb; | |
1788 | blocks[2] = join_bb; | |
1789 | renumber_gimple_stmt_uids_in_blocks (blocks, 3); | |
1790 | ||
1791 | /* Check that there are no read-after-write or write-after-write dependencies | |
1792 | in THEN_BB. */ | |
f1f41a6c | 1793 | FOR_EACH_VEC_ELT (then_ddrs, i, ddr) |
ec611e12 | 1794 | { |
1795 | struct data_reference *dra = DDR_A (ddr); | |
1796 | struct data_reference *drb = DDR_B (ddr); | |
1797 | ||
1798 | if (DDR_ARE_DEPENDENT (ddr) != chrec_known | |
1799 | && ((DR_IS_READ (dra) && DR_IS_WRITE (drb) | |
1800 | && gimple_uid (DR_STMT (dra)) > gimple_uid (DR_STMT (drb))) | |
1801 | || (DR_IS_READ (drb) && DR_IS_WRITE (dra) | |
1802 | && gimple_uid (DR_STMT (drb)) > gimple_uid (DR_STMT (dra))) | |
1803 | || (DR_IS_WRITE (dra) && DR_IS_WRITE (drb)))) | |
1804 | { | |
1805 | free_dependence_relations (then_ddrs); | |
1806 | free_dependence_relations (else_ddrs); | |
2473bfb7 | 1807 | free_data_refs (then_datarefs); |
1808 | free_data_refs (else_datarefs); | |
ec611e12 | 1809 | return false; |
1810 | } | |
1811 | } | |
1812 | ||
1813 | /* Check that there are no read-after-write or write-after-write dependencies | |
1814 | in ELSE_BB. */ | |
f1f41a6c | 1815 | FOR_EACH_VEC_ELT (else_ddrs, i, ddr) |
ec611e12 | 1816 | { |
1817 | struct data_reference *dra = DDR_A (ddr); | |
1818 | struct data_reference *drb = DDR_B (ddr); | |
1819 | ||
1820 | if (DDR_ARE_DEPENDENT (ddr) != chrec_known | |
1821 | && ((DR_IS_READ (dra) && DR_IS_WRITE (drb) | |
1822 | && gimple_uid (DR_STMT (dra)) > gimple_uid (DR_STMT (drb))) | |
1823 | || (DR_IS_READ (drb) && DR_IS_WRITE (dra) | |
1824 | && gimple_uid (DR_STMT (drb)) > gimple_uid (DR_STMT (dra))) | |
1825 | || (DR_IS_WRITE (dra) && DR_IS_WRITE (drb)))) | |
1826 | { | |
1827 | free_dependence_relations (then_ddrs); | |
1828 | free_dependence_relations (else_ddrs); | |
2473bfb7 | 1829 | free_data_refs (then_datarefs); |
1830 | free_data_refs (else_datarefs); | |
ec611e12 | 1831 | return false; |
1832 | } | |
1833 | } | |
1834 | ||
1835 | /* Sink stores with same LHS. */ | |
f1f41a6c | 1836 | FOR_EACH_VEC_ELT (then_stores, i, then_store) |
ec611e12 | 1837 | { |
f1f41a6c | 1838 | else_store = else_stores[i]; |
ec611e12 | 1839 | res = cond_if_else_store_replacement_1 (then_bb, else_bb, join_bb, |
1840 | then_store, else_store); | |
1841 | ok = ok || res; | |
1842 | } | |
1843 | ||
1844 | free_dependence_relations (then_ddrs); | |
1845 | free_dependence_relations (else_ddrs); | |
2473bfb7 | 1846 | free_data_refs (then_datarefs); |
1847 | free_data_refs (else_datarefs); | |
ec611e12 | 1848 | |
1849 | return ok; | |
1850 | } | |
1851 | ||
239e9670 | 1852 | /* Return TRUE if STMT has a VUSE whose corresponding VDEF is in BB. */ |
1853 | ||
1854 | static bool | |
1855 | local_mem_dependence (gimple stmt, basic_block bb) | |
1856 | { | |
1857 | tree vuse = gimple_vuse (stmt); | |
1858 | gimple def; | |
1859 | ||
1860 | if (!vuse) | |
1861 | return false; | |
1862 | ||
1863 | def = SSA_NAME_DEF_STMT (vuse); | |
1864 | return (def && gimple_bb (def) == bb); | |
1865 | } | |
1866 | ||
1867 | /* Given a "diamond" control-flow pattern where BB0 tests a condition, | |
1868 | BB1 and BB2 are "then" and "else" blocks dependent on this test, | |
f32420fb | 1869 | and BB3 rejoins control flow following BB1 and BB2, look for |
239e9670 | 1870 | opportunities to hoist loads as follows. If BB3 contains a PHI of |
1871 | two loads, one each occurring in BB1 and BB2, and the loads are | |
1872 | provably of adjacent fields in the same structure, then move both | |
1873 | loads into BB0. Of course this can only be done if there are no | |
1874 | dependencies preventing such motion. | |
1875 | ||
1876 | One of the hoisted loads will always be speculative, so the | |
1877 | transformation is currently conservative: | |
1878 | ||
1879 | - The fields must be strictly adjacent. | |
1880 | - The two fields must occupy a single memory block that is | |
1881 | guaranteed to not cross a page boundary. | |
1882 | ||
1883 | The last is difficult to prove, as such memory blocks should be | |
1884 | aligned on the minimum of the stack alignment boundary and the | |
1885 | alignment guaranteed by heap allocation interfaces. Thus we rely | |
1886 | on a parameter for the alignment value. | |
1887 | ||
1888 | Provided a good value is used for the last case, the first | |
1889 | restriction could possibly be relaxed. */ | |
1890 | ||
1891 | static void | |
1892 | hoist_adjacent_loads (basic_block bb0, basic_block bb1, | |
1893 | basic_block bb2, basic_block bb3) | |
1894 | { | |
1895 | int param_align = PARAM_VALUE (PARAM_L1_CACHE_LINE_SIZE); | |
1896 | unsigned param_align_bits = (unsigned) (param_align * BITS_PER_UNIT); | |
1a91d914 | 1897 | gphi_iterator gsi; |
239e9670 | 1898 | |
1899 | /* Walk the phis in bb3 looking for an opportunity. We are looking | |
1900 | for phis of two SSA names, one each of which is defined in bb1 and | |
1901 | bb2. */ | |
1902 | for (gsi = gsi_start_phis (bb3); !gsi_end_p (gsi); gsi_next (&gsi)) | |
1903 | { | |
1a91d914 | 1904 | gphi *phi_stmt = gsi.phi (); |
dfcf26a5 | 1905 | gimple def1, def2; |
1906 | tree arg1, arg2, ref1, ref2, field1, field2; | |
239e9670 | 1907 | tree tree_offset1, tree_offset2, tree_size2, next; |
1908 | int offset1, offset2, size2; | |
1909 | unsigned align1; | |
1910 | gimple_stmt_iterator gsi2; | |
1911 | basic_block bb_for_def1, bb_for_def2; | |
1912 | ||
7c782c9b | 1913 | if (gimple_phi_num_args (phi_stmt) != 2 |
1914 | || virtual_operand_p (gimple_phi_result (phi_stmt))) | |
239e9670 | 1915 | continue; |
1916 | ||
1917 | arg1 = gimple_phi_arg_def (phi_stmt, 0); | |
1918 | arg2 = gimple_phi_arg_def (phi_stmt, 1); | |
f32420fb | 1919 | |
239e9670 | 1920 | if (TREE_CODE (arg1) != SSA_NAME |
1921 | || TREE_CODE (arg2) != SSA_NAME | |
1922 | || SSA_NAME_IS_DEFAULT_DEF (arg1) | |
7c782c9b | 1923 | || SSA_NAME_IS_DEFAULT_DEF (arg2)) |
239e9670 | 1924 | continue; |
1925 | ||
1926 | def1 = SSA_NAME_DEF_STMT (arg1); | |
1927 | def2 = SSA_NAME_DEF_STMT (arg2); | |
1928 | ||
1929 | if ((gimple_bb (def1) != bb1 || gimple_bb (def2) != bb2) | |
1930 | && (gimple_bb (def2) != bb1 || gimple_bb (def1) != bb2)) | |
1931 | continue; | |
1932 | ||
1933 | /* Check the mode of the arguments to be sure a conditional move | |
1934 | can be generated for it. */ | |
935611bc | 1935 | if (optab_handler (movcc_optab, TYPE_MODE (TREE_TYPE (arg1))) |
1936 | == CODE_FOR_nothing) | |
239e9670 | 1937 | continue; |
1938 | ||
1939 | /* Both statements must be assignments whose RHS is a COMPONENT_REF. */ | |
1940 | if (!gimple_assign_single_p (def1) | |
6cc085b6 | 1941 | || !gimple_assign_single_p (def2) |
1942 | || gimple_has_volatile_ops (def1) | |
1943 | || gimple_has_volatile_ops (def2)) | |
239e9670 | 1944 | continue; |
1945 | ||
1946 | ref1 = gimple_assign_rhs1 (def1); | |
1947 | ref2 = gimple_assign_rhs1 (def2); | |
1948 | ||
1949 | if (TREE_CODE (ref1) != COMPONENT_REF | |
1950 | || TREE_CODE (ref2) != COMPONENT_REF) | |
1951 | continue; | |
1952 | ||
1953 | /* The zeroth operand of the two component references must be | |
1954 | identical. It is not sufficient to compare get_base_address of | |
1955 | the two references, because this could allow for different | |
1956 | elements of the same array in the two trees. It is not safe to | |
1957 | assume that the existence of one array element implies the | |
1958 | existence of a different one. */ | |
1959 | if (!operand_equal_p (TREE_OPERAND (ref1, 0), TREE_OPERAND (ref2, 0), 0)) | |
1960 | continue; | |
1961 | ||
1962 | field1 = TREE_OPERAND (ref1, 1); | |
1963 | field2 = TREE_OPERAND (ref2, 1); | |
1964 | ||
1965 | /* Check for field adjacency, and ensure field1 comes first. */ | |
1966 | for (next = DECL_CHAIN (field1); | |
1967 | next && TREE_CODE (next) != FIELD_DECL; | |
1968 | next = DECL_CHAIN (next)) | |
1969 | ; | |
1970 | ||
1971 | if (next != field2) | |
1972 | { | |
1973 | for (next = DECL_CHAIN (field2); | |
1974 | next && TREE_CODE (next) != FIELD_DECL; | |
1975 | next = DECL_CHAIN (next)) | |
1976 | ; | |
1977 | ||
1978 | if (next != field1) | |
1979 | continue; | |
1980 | ||
dfcf26a5 | 1981 | std::swap (field1, field2); |
1982 | std::swap (def1, def2); | |
239e9670 | 1983 | } |
1984 | ||
7c74ee50 | 1985 | bb_for_def1 = gimple_bb (def1); |
1986 | bb_for_def2 = gimple_bb (def2); | |
1987 | ||
239e9670 | 1988 | /* Check for proper alignment of the first field. */ |
1989 | tree_offset1 = bit_position (field1); | |
1990 | tree_offset2 = bit_position (field2); | |
1991 | tree_size2 = DECL_SIZE (field2); | |
1992 | ||
e913b5cd | 1993 | if (!tree_fits_uhwi_p (tree_offset1) |
1994 | || !tree_fits_uhwi_p (tree_offset2) | |
1995 | || !tree_fits_uhwi_p (tree_size2)) | |
239e9670 | 1996 | continue; |
1997 | ||
e913b5cd | 1998 | offset1 = tree_to_uhwi (tree_offset1); |
1999 | offset2 = tree_to_uhwi (tree_offset2); | |
2000 | size2 = tree_to_uhwi (tree_size2); | |
239e9670 | 2001 | align1 = DECL_ALIGN (field1) % param_align_bits; |
2002 | ||
2003 | if (offset1 % BITS_PER_UNIT != 0) | |
2004 | continue; | |
2005 | ||
2006 | /* For profitability, the two field references should fit within | |
2007 | a single cache line. */ | |
2008 | if (align1 + offset2 - offset1 + size2 > param_align_bits) | |
2009 | continue; | |
2010 | ||
2011 | /* The two expressions cannot be dependent upon vdefs defined | |
2012 | in bb1/bb2. */ | |
2013 | if (local_mem_dependence (def1, bb_for_def1) | |
2014 | || local_mem_dependence (def2, bb_for_def2)) | |
2015 | continue; | |
2016 | ||
2017 | /* The conditions are satisfied; hoist the loads from bb1 and bb2 into | |
2018 | bb0. We hoist the first one first so that a cache miss is handled | |
2019 | efficiently regardless of hardware cache-fill policy. */ | |
2020 | gsi2 = gsi_for_stmt (def1); | |
2021 | gsi_move_to_bb_end (&gsi2, bb0); | |
2022 | gsi2 = gsi_for_stmt (def2); | |
2023 | gsi_move_to_bb_end (&gsi2, bb0); | |
2024 | ||
2025 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2026 | { | |
2027 | fprintf (dump_file, | |
2028 | "\nHoisting adjacent loads from %d and %d into %d: \n", | |
2029 | bb_for_def1->index, bb_for_def2->index, bb0->index); | |
2030 | print_gimple_stmt (dump_file, def1, 0, TDF_VOPS|TDF_MEMSYMS); | |
2031 | print_gimple_stmt (dump_file, def2, 0, TDF_VOPS|TDF_MEMSYMS); | |
2032 | } | |
2033 | } | |
2034 | } | |
2035 | ||
2036 | /* Determine whether we should attempt to hoist adjacent loads out of | |
2037 | diamond patterns in pass_phiopt. Always hoist loads if | |
2038 | -fhoist-adjacent-loads is specified and the target machine has | |
6f0ddab1 | 2039 | both a conditional move instruction and a defined cache line size. */ |
239e9670 | 2040 | |
2041 | static bool | |
2042 | gate_hoist_loads (void) | |
2043 | { | |
6f0ddab1 | 2044 | return (flag_hoist_adjacent_loads == 1 |
2045 | && PARAM_VALUE (PARAM_L1_CACHE_LINE_SIZE) | |
2046 | && HAVE_conditional_move); | |
239e9670 | 2047 | } |
2048 | ||
65b0537f | 2049 | /* This pass tries to replaces an if-then-else block with an |
2050 | assignment. We have four kinds of transformations. Some of these | |
2051 | transformations are also performed by the ifcvt RTL optimizer. | |
2052 | ||
2053 | Conditional Replacement | |
2054 | ----------------------- | |
2055 | ||
2056 | This transformation, implemented in conditional_replacement, | |
2057 | replaces | |
2058 | ||
2059 | bb0: | |
2060 | if (cond) goto bb2; else goto bb1; | |
2061 | bb1: | |
2062 | bb2: | |
2063 | x = PHI <0 (bb1), 1 (bb0), ...>; | |
2064 | ||
2065 | with | |
2066 | ||
2067 | bb0: | |
2068 | x' = cond; | |
2069 | goto bb2; | |
2070 | bb2: | |
2071 | x = PHI <x' (bb0), ...>; | |
2072 | ||
2073 | We remove bb1 as it becomes unreachable. This occurs often due to | |
2074 | gimplification of conditionals. | |
2075 | ||
2076 | Value Replacement | |
2077 | ----------------- | |
2078 | ||
2079 | This transformation, implemented in value_replacement, replaces | |
2080 | ||
2081 | bb0: | |
2082 | if (a != b) goto bb2; else goto bb1; | |
2083 | bb1: | |
2084 | bb2: | |
2085 | x = PHI <a (bb1), b (bb0), ...>; | |
2086 | ||
2087 | with | |
2088 | ||
2089 | bb0: | |
2090 | bb2: | |
2091 | x = PHI <b (bb0), ...>; | |
2092 | ||
2093 | This opportunity can sometimes occur as a result of other | |
2094 | optimizations. | |
2095 | ||
2096 | ||
2097 | Another case caught by value replacement looks like this: | |
2098 | ||
2099 | bb0: | |
2100 | t1 = a == CONST; | |
2101 | t2 = b > c; | |
2102 | t3 = t1 & t2; | |
2103 | if (t3 != 0) goto bb1; else goto bb2; | |
2104 | bb1: | |
2105 | bb2: | |
2106 | x = PHI (CONST, a) | |
2107 | ||
2108 | Gets replaced with: | |
2109 | bb0: | |
2110 | bb2: | |
2111 | t1 = a == CONST; | |
2112 | t2 = b > c; | |
2113 | t3 = t1 & t2; | |
2114 | x = a; | |
2115 | ||
2116 | ABS Replacement | |
2117 | --------------- | |
2118 | ||
2119 | This transformation, implemented in abs_replacement, replaces | |
2120 | ||
2121 | bb0: | |
2122 | if (a >= 0) goto bb2; else goto bb1; | |
2123 | bb1: | |
2124 | x = -a; | |
2125 | bb2: | |
2126 | x = PHI <x (bb1), a (bb0), ...>; | |
2127 | ||
2128 | with | |
2129 | ||
2130 | bb0: | |
2131 | x' = ABS_EXPR< a >; | |
2132 | bb2: | |
2133 | x = PHI <x' (bb0), ...>; | |
2134 | ||
2135 | MIN/MAX Replacement | |
2136 | ------------------- | |
2137 | ||
2138 | This transformation, minmax_replacement replaces | |
2139 | ||
2140 | bb0: | |
2141 | if (a <= b) goto bb2; else goto bb1; | |
2142 | bb1: | |
2143 | bb2: | |
2144 | x = PHI <b (bb1), a (bb0), ...>; | |
2145 | ||
2146 | with | |
2147 | ||
2148 | bb0: | |
2149 | x' = MIN_EXPR (a, b) | |
2150 | bb2: | |
2151 | x = PHI <x' (bb0), ...>; | |
2152 | ||
2153 | A similar transformation is done for MAX_EXPR. | |
2154 | ||
2155 | ||
2156 | This pass also performs a fifth transformation of a slightly different | |
2157 | flavor. | |
2158 | ||
2159 | Adjacent Load Hoisting | |
2160 | ---------------------- | |
2161 | ||
2162 | This transformation replaces | |
2163 | ||
2164 | bb0: | |
2165 | if (...) goto bb2; else goto bb1; | |
2166 | bb1: | |
2167 | x1 = (<expr>).field1; | |
2168 | goto bb3; | |
2169 | bb2: | |
2170 | x2 = (<expr>).field2; | |
2171 | bb3: | |
2172 | # x = PHI <x1, x2>; | |
2173 | ||
2174 | with | |
2175 | ||
2176 | bb0: | |
2177 | x1 = (<expr>).field1; | |
2178 | x2 = (<expr>).field2; | |
2179 | if (...) goto bb2; else goto bb1; | |
2180 | bb1: | |
2181 | goto bb3; | |
2182 | bb2: | |
2183 | bb3: | |
2184 | # x = PHI <x1, x2>; | |
2185 | ||
2186 | The purpose of this transformation is to enable generation of conditional | |
2187 | move instructions such as Intel CMOVE or PowerPC ISEL. Because one of | |
2188 | the loads is speculative, the transformation is restricted to very | |
2189 | specific cases to avoid introducing a page fault. We are looking for | |
2190 | the common idiom: | |
2191 | ||
2192 | if (...) | |
2193 | x = y->left; | |
2194 | else | |
2195 | x = y->right; | |
2196 | ||
2197 | where left and right are typically adjacent pointers in a tree structure. */ | |
20e5647c | 2198 | |
cbe8bda8 | 2199 | namespace { |
2200 | ||
2201 | const pass_data pass_data_phiopt = | |
4ee9c684 | 2202 | { |
cbe8bda8 | 2203 | GIMPLE_PASS, /* type */ |
2204 | "phiopt", /* name */ | |
2205 | OPTGROUP_NONE, /* optinfo_flags */ | |
cbe8bda8 | 2206 | TV_TREE_PHIOPT, /* tv_id */ |
2207 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
2208 | 0, /* properties_provided */ | |
2209 | 0, /* properties_destroyed */ | |
2210 | 0, /* todo_flags_start */ | |
8b88439e | 2211 | 0, /* todo_flags_finish */ |
4ee9c684 | 2212 | }; |
e6d0e152 | 2213 | |
cbe8bda8 | 2214 | class pass_phiopt : public gimple_opt_pass |
2215 | { | |
2216 | public: | |
9af5ce0c | 2217 | pass_phiopt (gcc::context *ctxt) |
2218 | : gimple_opt_pass (pass_data_phiopt, ctxt) | |
cbe8bda8 | 2219 | {} |
2220 | ||
2221 | /* opt_pass methods: */ | |
ae84f584 | 2222 | opt_pass * clone () { return new pass_phiopt (m_ctxt); } |
3dac50cc | 2223 | virtual bool gate (function *) { return flag_ssa_phiopt; } |
65b0537f | 2224 | virtual unsigned int execute (function *) |
2225 | { | |
2226 | return tree_ssa_phiopt_worker (false, gate_hoist_loads ()); | |
2227 | } | |
cbe8bda8 | 2228 | |
2229 | }; // class pass_phiopt | |
2230 | ||
2231 | } // anon namespace | |
2232 | ||
2233 | gimple_opt_pass * | |
2234 | make_pass_phiopt (gcc::context *ctxt) | |
2235 | { | |
2236 | return new pass_phiopt (ctxt); | |
2237 | } | |
2238 | ||
cbe8bda8 | 2239 | namespace { |
2240 | ||
2241 | const pass_data pass_data_cselim = | |
e6d0e152 | 2242 | { |
cbe8bda8 | 2243 | GIMPLE_PASS, /* type */ |
2244 | "cselim", /* name */ | |
2245 | OPTGROUP_NONE, /* optinfo_flags */ | |
cbe8bda8 | 2246 | TV_TREE_PHIOPT, /* tv_id */ |
2247 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
2248 | 0, /* properties_provided */ | |
2249 | 0, /* properties_destroyed */ | |
2250 | 0, /* todo_flags_start */ | |
8b88439e | 2251 | 0, /* todo_flags_finish */ |
e6d0e152 | 2252 | }; |
cbe8bda8 | 2253 | |
2254 | class pass_cselim : public gimple_opt_pass | |
2255 | { | |
2256 | public: | |
9af5ce0c | 2257 | pass_cselim (gcc::context *ctxt) |
2258 | : gimple_opt_pass (pass_data_cselim, ctxt) | |
cbe8bda8 | 2259 | {} |
2260 | ||
2261 | /* opt_pass methods: */ | |
31315c24 | 2262 | virtual bool gate (function *) { return flag_tree_cselim; } |
65b0537f | 2263 | virtual unsigned int execute (function *) { return tree_ssa_cs_elim (); } |
cbe8bda8 | 2264 | |
2265 | }; // class pass_cselim | |
2266 | ||
2267 | } // anon namespace | |
2268 | ||
2269 | gimple_opt_pass * | |
2270 | make_pass_cselim (gcc::context *ctxt) | |
2271 | { | |
2272 | return new pass_cselim (ctxt); | |
2273 | } |