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4ee9c684 | 1 | /* Optimization of PHI nodes by converting them into straightline code. |
aad93da1 | 2 | Copyright (C) 2004-2017 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" | |
9ef16211 | 23 | #include "backend.h" |
7c29e30e | 24 | #include "insn-codes.h" |
25 | #include "rtl.h" | |
4ee9c684 | 26 | #include "tree.h" |
9ef16211 | 27 | #include "gimple.h" |
7c29e30e | 28 | #include "cfghooks.h" |
29 | #include "tree-pass.h" | |
9ef16211 | 30 | #include "ssa.h" |
7c29e30e | 31 | #include "optabs-tree.h" |
32 | #include "insn-config.h" | |
33 | #include "gimple-pretty-print.h" | |
b20a8bb4 | 34 | #include "fold-const.h" |
9ed99284 | 35 | #include "stor-layout.h" |
94ea8568 | 36 | #include "cfganal.h" |
a8783bee | 37 | #include "gimplify.h" |
dcf1a1ec | 38 | #include "gimple-iterator.h" |
e795d6e1 | 39 | #include "gimplify-me.h" |
073c1fd5 | 40 | #include "tree-cfg.h" |
073c1fd5 | 41 | #include "tree-dfa.h" |
e6d0e152 | 42 | #include "domwalk.h" |
ec611e12 | 43 | #include "cfgloop.h" |
44 | #include "tree-data-ref.h" | |
f6568ea4 | 45 | #include "tree-scalar-evolution.h" |
b6814ca0 | 46 | #include "tree-inline.h" |
0d8001a7 | 47 | #include "params.h" |
239e9670 | 48 | |
239e9670 | 49 | static unsigned int tree_ssa_phiopt_worker (bool, bool); |
a4844041 | 50 | static bool conditional_replacement (basic_block, basic_block, |
1a91d914 | 51 | edge, edge, gphi *, tree, tree); |
8100256d | 52 | static gphi *factor_out_conditional_conversion (edge, edge, gphi *, tree, tree, |
53 | gimple *); | |
fb9912ea | 54 | static int value_replacement (basic_block, basic_block, |
42acab1c | 55 | edge, edge, gimple *, tree, tree); |
a4844041 | 56 | static bool minmax_replacement (basic_block, basic_block, |
42acab1c | 57 | edge, edge, gimple *, tree, tree); |
a4844041 | 58 | static bool abs_replacement (basic_block, basic_block, |
42acab1c | 59 | edge, edge, gimple *, tree, tree); |
e6d0e152 | 60 | static bool cond_store_replacement (basic_block, basic_block, edge, edge, |
431205b7 | 61 | hash_set<tree> *); |
91cf53d5 | 62 | static bool cond_if_else_store_replacement (basic_block, basic_block, basic_block); |
431205b7 | 63 | static hash_set<tree> * get_non_trapping (); |
42acab1c | 64 | static void replace_phi_edge_with_variable (basic_block, edge, gimple *, tree); |
239e9670 | 65 | static void hoist_adjacent_loads (basic_block, basic_block, |
66 | basic_block, basic_block); | |
67 | static bool gate_hoist_loads (void); | |
902929aa | 68 | |
e6d0e152 | 69 | /* This pass tries to transform conditional stores into unconditional |
70 | ones, enabling further simplifications with the simpler then and else | |
71 | blocks. In particular it replaces this: | |
72 | ||
73 | bb0: | |
74 | if (cond) goto bb2; else goto bb1; | |
75 | bb1: | |
91cf53d5 | 76 | *p = RHS; |
e6d0e152 | 77 | bb2: |
78 | ||
79 | with | |
80 | ||
81 | bb0: | |
82 | if (cond) goto bb1; else goto bb2; | |
83 | bb1: | |
84 | condtmp' = *p; | |
85 | bb2: | |
86 | condtmp = PHI <RHS, condtmp'> | |
91cf53d5 | 87 | *p = condtmp; |
e6d0e152 | 88 | |
89 | This transformation can only be done under several constraints, | |
91cf53d5 | 90 | documented below. It also replaces: |
91 | ||
92 | bb0: | |
93 | if (cond) goto bb2; else goto bb1; | |
94 | bb1: | |
95 | *p = RHS1; | |
96 | goto bb3; | |
97 | bb2: | |
98 | *p = RHS2; | |
99 | bb3: | |
100 | ||
101 | with | |
102 | ||
103 | bb0: | |
104 | if (cond) goto bb3; else goto bb1; | |
105 | bb1: | |
106 | bb3: | |
107 | condtmp = PHI <RHS1, RHS2> | |
108 | *p = condtmp; */ | |
e6d0e152 | 109 | |
110 | static unsigned int | |
111 | tree_ssa_cs_elim (void) | |
112 | { | |
f6568ea4 | 113 | unsigned todo; |
114 | /* ??? We are not interested in loop related info, but the following | |
115 | will create it, ICEing as we didn't init loops with pre-headers. | |
116 | An interfacing issue of find_data_references_in_bb. */ | |
117 | loop_optimizer_init (LOOPS_NORMAL); | |
118 | scev_initialize (); | |
119 | todo = tree_ssa_phiopt_worker (true, false); | |
120 | scev_finalize (); | |
121 | loop_optimizer_finalize (); | |
122 | return todo; | |
e6d0e152 | 123 | } |
124 | ||
c3597b05 | 125 | /* Return the singleton PHI in the SEQ of PHIs for edges E0 and E1. */ |
126 | ||
1a91d914 | 127 | static gphi * |
c3597b05 | 128 | single_non_singleton_phi_for_edges (gimple_seq seq, edge e0, edge e1) |
129 | { | |
130 | gimple_stmt_iterator i; | |
1a91d914 | 131 | gphi *phi = NULL; |
c3597b05 | 132 | if (gimple_seq_singleton_p (seq)) |
1a91d914 | 133 | return as_a <gphi *> (gsi_stmt (gsi_start (seq))); |
c3597b05 | 134 | for (i = gsi_start (seq); !gsi_end_p (i); gsi_next (&i)) |
135 | { | |
1a91d914 | 136 | gphi *p = as_a <gphi *> (gsi_stmt (i)); |
c3597b05 | 137 | /* If the PHI arguments are equal then we can skip this PHI. */ |
138 | if (operand_equal_for_phi_arg_p (gimple_phi_arg_def (p, e0->dest_idx), | |
139 | gimple_phi_arg_def (p, e1->dest_idx))) | |
140 | continue; | |
141 | ||
142 | /* If we already have a PHI that has the two edge arguments are | |
143 | different, then return it is not a singleton for these PHIs. */ | |
144 | if (phi) | |
145 | return NULL; | |
146 | ||
147 | phi = p; | |
148 | } | |
149 | return phi; | |
150 | } | |
151 | ||
e6d0e152 | 152 | /* The core routine of conditional store replacement and normal |
153 | phi optimizations. Both share much of the infrastructure in how | |
154 | to match applicable basic block patterns. DO_STORE_ELIM is true | |
239e9670 | 155 | when we want to do conditional store replacement, false otherwise. |
f32420fb | 156 | DO_HOIST_LOADS is true when we want to hoist adjacent loads out |
239e9670 | 157 | of diamond control flow patterns, false otherwise. */ |
e6d0e152 | 158 | static unsigned int |
239e9670 | 159 | tree_ssa_phiopt_worker (bool do_store_elim, bool do_hoist_loads) |
4ee9c684 | 160 | { |
161 | basic_block bb; | |
194899bf | 162 | basic_block *bb_order; |
163 | unsigned n, i; | |
1e4b21e3 | 164 | bool cfgchanged = false; |
431205b7 | 165 | hash_set<tree> *nontrap = 0; |
e6d0e152 | 166 | |
167 | if (do_store_elim) | |
03d37e4e | 168 | /* Calculate the set of non-trapping memory accesses. */ |
169 | nontrap = get_non_trapping (); | |
194899bf | 170 | |
171 | /* Search every basic block for COND_EXPR we may be able to optimize. | |
172 | ||
173 | We walk the blocks in order that guarantees that a block with | |
174 | a single predecessor is processed before the predecessor. | |
175 | This ensures that we collapse inner ifs before visiting the | |
176 | outer ones, and also that we do not try to visit a removed | |
177 | block. */ | |
ba4d2b2f | 178 | bb_order = single_pred_before_succ_order (); |
a28770e1 | 179 | n = n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS; |
4ee9c684 | 180 | |
48e1416a | 181 | for (i = 0; i < n; i++) |
4ee9c684 | 182 | { |
42acab1c | 183 | gimple *cond_stmt; |
1a91d914 | 184 | gphi *phi; |
33784d89 | 185 | basic_block bb1, bb2; |
186 | edge e1, e2; | |
194899bf | 187 | tree arg0, arg1; |
188 | ||
189 | bb = bb_order[i]; | |
20e5647c | 190 | |
75a70cf9 | 191 | cond_stmt = last_stmt (bb); |
192 | /* Check to see if the last statement is a GIMPLE_COND. */ | |
193 | if (!cond_stmt | |
194 | || gimple_code (cond_stmt) != GIMPLE_COND) | |
33784d89 | 195 | continue; |
20e5647c | 196 | |
33784d89 | 197 | e1 = EDGE_SUCC (bb, 0); |
198 | bb1 = e1->dest; | |
199 | e2 = EDGE_SUCC (bb, 1); | |
200 | bb2 = e2->dest; | |
20e5647c | 201 | |
33784d89 | 202 | /* We cannot do the optimization on abnormal edges. */ |
203 | if ((e1->flags & EDGE_ABNORMAL) != 0 | |
204 | || (e2->flags & EDGE_ABNORMAL) != 0) | |
205 | continue; | |
20e5647c | 206 | |
33784d89 | 207 | /* If either bb1's succ or bb2 or bb2's succ is non NULL. */ |
ea091dfd | 208 | if (EDGE_COUNT (bb1->succs) == 0 |
33784d89 | 209 | || bb2 == NULL |
ea091dfd | 210 | || EDGE_COUNT (bb2->succs) == 0) |
33784d89 | 211 | continue; |
20e5647c | 212 | |
33784d89 | 213 | /* Find the bb which is the fall through to the other. */ |
214 | if (EDGE_SUCC (bb1, 0)->dest == bb2) | |
215 | ; | |
216 | else if (EDGE_SUCC (bb2, 0)->dest == bb1) | |
217 | { | |
a4f59596 | 218 | std::swap (bb1, bb2); |
219 | std::swap (e1, e2); | |
33784d89 | 220 | } |
91cf53d5 | 221 | else if (do_store_elim |
222 | && EDGE_SUCC (bb1, 0)->dest == EDGE_SUCC (bb2, 0)->dest) | |
223 | { | |
224 | basic_block bb3 = EDGE_SUCC (bb1, 0)->dest; | |
225 | ||
226 | if (!single_succ_p (bb1) | |
227 | || (EDGE_SUCC (bb1, 0)->flags & EDGE_FALLTHRU) == 0 | |
228 | || !single_succ_p (bb2) | |
229 | || (EDGE_SUCC (bb2, 0)->flags & EDGE_FALLTHRU) == 0 | |
230 | || EDGE_COUNT (bb3->preds) != 2) | |
231 | continue; | |
232 | if (cond_if_else_store_replacement (bb1, bb2, bb3)) | |
233 | cfgchanged = true; | |
234 | continue; | |
235 | } | |
239e9670 | 236 | else if (do_hoist_loads |
8100256d | 237 | && EDGE_SUCC (bb1, 0)->dest == EDGE_SUCC (bb2, 0)->dest) |
239e9670 | 238 | { |
239 | basic_block bb3 = EDGE_SUCC (bb1, 0)->dest; | |
240 | ||
241 | if (!FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (cond_stmt))) | |
242 | && single_succ_p (bb1) | |
243 | && single_succ_p (bb2) | |
244 | && single_pred_p (bb1) | |
245 | && single_pred_p (bb2) | |
246 | && EDGE_COUNT (bb->succs) == 2 | |
247 | && EDGE_COUNT (bb3->preds) == 2 | |
248 | /* If one edge or the other is dominant, a conditional move | |
249 | is likely to perform worse than the well-predicted branch. */ | |
250 | && !predictable_edge_p (EDGE_SUCC (bb, 0)) | |
251 | && !predictable_edge_p (EDGE_SUCC (bb, 1))) | |
252 | hoist_adjacent_loads (bb, bb1, bb2, bb3); | |
253 | continue; | |
254 | } | |
33784d89 | 255 | else |
f32420fb | 256 | continue; |
20e5647c | 257 | |
33784d89 | 258 | e1 = EDGE_SUCC (bb1, 0); |
20e5647c | 259 | |
33784d89 | 260 | /* Make sure that bb1 is just a fall through. */ |
db5ba14c | 261 | if (!single_succ_p (bb1) |
33784d89 | 262 | || (e1->flags & EDGE_FALLTHRU) == 0) |
263 | continue; | |
20e5647c | 264 | |
3472707f | 265 | /* Also make sure that bb1 only have one predecessor and that it |
266 | is bb. */ | |
ea091dfd | 267 | if (!single_pred_p (bb1) |
268 | || single_pred (bb1) != bb) | |
33784d89 | 269 | continue; |
20e5647c | 270 | |
e6d0e152 | 271 | if (do_store_elim) |
272 | { | |
273 | /* bb1 is the middle block, bb2 the join block, bb the split block, | |
274 | e1 the fallthrough edge from bb1 to bb2. We can't do the | |
275 | optimization if the join block has more than two predecessors. */ | |
276 | if (EDGE_COUNT (bb2->preds) > 2) | |
277 | continue; | |
278 | if (cond_store_replacement (bb1, bb2, e1, e2, nontrap)) | |
279 | cfgchanged = true; | |
280 | } | |
281 | else | |
282 | { | |
75a70cf9 | 283 | gimple_seq phis = phi_nodes (bb2); |
2109076a | 284 | gimple_stmt_iterator gsi; |
fb9912ea | 285 | bool candorest = true; |
c3597b05 | 286 | |
fb9912ea | 287 | /* Value replacement can work with more than one PHI |
288 | so try that first. */ | |
289 | for (gsi = gsi_start (phis); !gsi_end_p (gsi); gsi_next (&gsi)) | |
290 | { | |
1a91d914 | 291 | phi = as_a <gphi *> (gsi_stmt (gsi)); |
fb9912ea | 292 | arg0 = gimple_phi_arg_def (phi, e1->dest_idx); |
293 | arg1 = gimple_phi_arg_def (phi, e2->dest_idx); | |
294 | if (value_replacement (bb, bb1, e1, e2, phi, arg0, arg1) == 2) | |
295 | { | |
296 | candorest = false; | |
297 | cfgchanged = true; | |
298 | break; | |
299 | } | |
300 | } | |
e6d0e152 | 301 | |
fb9912ea | 302 | if (!candorest) |
303 | continue; | |
f32420fb | 304 | |
c3597b05 | 305 | phi = single_non_singleton_phi_for_edges (phis, e1, e2); |
2109076a | 306 | if (!phi) |
e6d0e152 | 307 | continue; |
308 | ||
75a70cf9 | 309 | arg0 = gimple_phi_arg_def (phi, e1->dest_idx); |
310 | arg1 = gimple_phi_arg_def (phi, e2->dest_idx); | |
e6d0e152 | 311 | |
312 | /* Something is wrong if we cannot find the arguments in the PHI | |
313 | node. */ | |
5dccd071 | 314 | gcc_assert (arg0 != NULL_TREE && arg1 != NULL_TREE); |
e6d0e152 | 315 | |
5dccd071 | 316 | gphi *newphi = factor_out_conditional_conversion (e1, e2, phi, |
8100256d | 317 | arg0, arg1, |
318 | cond_stmt); | |
5dccd071 | 319 | if (newphi != NULL) |
29a78fec | 320 | { |
5dccd071 | 321 | phi = newphi; |
29a78fec | 322 | /* factor_out_conditional_conversion may create a new PHI in |
323 | BB2 and eliminate an existing PHI in BB2. Recompute values | |
324 | that may be affected by that change. */ | |
29a78fec | 325 | arg0 = gimple_phi_arg_def (phi, e1->dest_idx); |
326 | arg1 = gimple_phi_arg_def (phi, e2->dest_idx); | |
5dccd071 | 327 | gcc_assert (arg0 != NULL_TREE && arg1 != NULL_TREE); |
29a78fec | 328 | } |
329 | ||
e6d0e152 | 330 | /* Do the replacement of conditional if it can be done. */ |
331 | if (conditional_replacement (bb, bb1, e1, e2, phi, arg0, arg1)) | |
332 | cfgchanged = true; | |
e6d0e152 | 333 | else if (abs_replacement (bb, bb1, e1, e2, phi, arg0, arg1)) |
334 | cfgchanged = true; | |
335 | else if (minmax_replacement (bb, bb1, e1, e2, phi, arg0, arg1)) | |
336 | cfgchanged = true; | |
337 | } | |
194899bf | 338 | } |
339 | ||
340 | free (bb_order); | |
48e1416a | 341 | |
e6d0e152 | 342 | if (do_store_elim) |
431205b7 | 343 | delete nontrap; |
e6d0e152 | 344 | /* If the CFG has changed, we should cleanup the CFG. */ |
345 | if (cfgchanged && do_store_elim) | |
346 | { | |
347 | /* In cond-store replacement we have added some loads on edges | |
348 | and new VOPS (as we moved the store, and created a load). */ | |
75a70cf9 | 349 | gsi_commit_edge_inserts (); |
e6d0e152 | 350 | return TODO_cleanup_cfg | TODO_update_ssa_only_virtuals; |
351 | } | |
352 | else if (cfgchanged) | |
353 | return TODO_cleanup_cfg; | |
354 | return 0; | |
194899bf | 355 | } |
356 | ||
fccee353 | 357 | /* Replace PHI node element whose edge is E in block BB with variable NEW. |
33784d89 | 358 | Remove the edge from COND_BLOCK which does not lead to BB (COND_BLOCK |
902929aa | 359 | is known to have two edges, one of which must reach BB). */ |
360 | ||
361 | static void | |
a4844041 | 362 | replace_phi_edge_with_variable (basic_block cond_block, |
42acab1c | 363 | edge e, gimple *phi, tree new_tree) |
902929aa | 364 | { |
75a70cf9 | 365 | basic_block bb = gimple_bb (phi); |
0e1a77e1 | 366 | basic_block block_to_remove; |
75a70cf9 | 367 | gimple_stmt_iterator gsi; |
33784d89 | 368 | |
20e5647c | 369 | /* Change the PHI argument to new. */ |
f0d6e81c | 370 | SET_USE (PHI_ARG_DEF_PTR (phi, e->dest_idx), new_tree); |
0e1a77e1 | 371 | |
0e1a77e1 | 372 | /* Remove the empty basic block. */ |
cd665a06 | 373 | if (EDGE_SUCC (cond_block, 0)->dest == bb) |
902929aa | 374 | { |
cd665a06 | 375 | EDGE_SUCC (cond_block, 0)->flags |= EDGE_FALLTHRU; |
376 | EDGE_SUCC (cond_block, 0)->flags &= ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE); | |
720cfc43 | 377 | EDGE_SUCC (cond_block, 0)->probability = profile_probability::always (); |
81c5be57 | 378 | EDGE_SUCC (cond_block, 0)->count += EDGE_SUCC (cond_block, 1)->count; |
0e1a77e1 | 379 | |
cd665a06 | 380 | block_to_remove = EDGE_SUCC (cond_block, 1)->dest; |
902929aa | 381 | } |
382 | else | |
383 | { | |
cd665a06 | 384 | EDGE_SUCC (cond_block, 1)->flags |= EDGE_FALLTHRU; |
385 | EDGE_SUCC (cond_block, 1)->flags | |
902929aa | 386 | &= ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE); |
720cfc43 | 387 | EDGE_SUCC (cond_block, 1)->probability = profile_probability::always (); |
81c5be57 | 388 | EDGE_SUCC (cond_block, 1)->count += EDGE_SUCC (cond_block, 0)->count; |
0e1a77e1 | 389 | |
cd665a06 | 390 | block_to_remove = EDGE_SUCC (cond_block, 0)->dest; |
902929aa | 391 | } |
0e1a77e1 | 392 | delete_basic_block (block_to_remove); |
20e5647c | 393 | |
902929aa | 394 | /* Eliminate the COND_EXPR at the end of COND_BLOCK. */ |
75a70cf9 | 395 | gsi = gsi_last_bb (cond_block); |
396 | gsi_remove (&gsi, true); | |
20e5647c | 397 | |
902929aa | 398 | if (dump_file && (dump_flags & TDF_DETAILS)) |
399 | fprintf (dump_file, | |
400 | "COND_EXPR in block %d and PHI in block %d converted to straightline code.\n", | |
401 | cond_block->index, | |
402 | bb->index); | |
403 | } | |
404 | ||
29a78fec | 405 | /* PR66726: Factor conversion out of COND_EXPR. If the arguments of the PHI |
406 | stmt are CONVERT_STMT, factor out the conversion and perform the conversion | |
8100256d | 407 | to the result of PHI stmt. COND_STMT is the controlling predicate. |
408 | Return the newly-created PHI, if any. */ | |
29a78fec | 409 | |
5dccd071 | 410 | static gphi * |
29a78fec | 411 | factor_out_conditional_conversion (edge e0, edge e1, gphi *phi, |
8100256d | 412 | tree arg0, tree arg1, gimple *cond_stmt) |
29a78fec | 413 | { |
42acab1c | 414 | gimple *arg0_def_stmt = NULL, *arg1_def_stmt = NULL, *new_stmt; |
29a78fec | 415 | tree new_arg0 = NULL_TREE, new_arg1 = NULL_TREE; |
416 | tree temp, result; | |
417 | gphi *newphi; | |
418 | gimple_stmt_iterator gsi, gsi_for_def; | |
419 | source_location locus = gimple_location (phi); | |
420 | enum tree_code convert_code; | |
421 | ||
422 | /* Handle only PHI statements with two arguments. TODO: If all | |
423 | other arguments to PHI are INTEGER_CST or if their defining | |
424 | statement have the same unary operation, we can handle more | |
425 | than two arguments too. */ | |
426 | if (gimple_phi_num_args (phi) != 2) | |
5dccd071 | 427 | return NULL; |
29a78fec | 428 | |
429 | /* First canonicalize to simplify tests. */ | |
430 | if (TREE_CODE (arg0) != SSA_NAME) | |
431 | { | |
432 | std::swap (arg0, arg1); | |
433 | std::swap (e0, e1); | |
434 | } | |
435 | ||
436 | if (TREE_CODE (arg0) != SSA_NAME | |
437 | || (TREE_CODE (arg1) != SSA_NAME | |
438 | && TREE_CODE (arg1) != INTEGER_CST)) | |
5dccd071 | 439 | return NULL; |
29a78fec | 440 | |
441 | /* Check if arg0 is an SSA_NAME and the stmt which defines arg0 is | |
442 | a conversion. */ | |
443 | arg0_def_stmt = SSA_NAME_DEF_STMT (arg0); | |
552821b4 | 444 | if (!gimple_assign_cast_p (arg0_def_stmt)) |
5dccd071 | 445 | return NULL; |
29a78fec | 446 | |
447 | /* Use the RHS as new_arg0. */ | |
448 | convert_code = gimple_assign_rhs_code (arg0_def_stmt); | |
449 | new_arg0 = gimple_assign_rhs1 (arg0_def_stmt); | |
450 | if (convert_code == VIEW_CONVERT_EXPR) | |
552821b4 | 451 | { |
452 | new_arg0 = TREE_OPERAND (new_arg0, 0); | |
453 | if (!is_gimple_reg_type (TREE_TYPE (new_arg0))) | |
454 | return NULL; | |
455 | } | |
29a78fec | 456 | |
457 | if (TREE_CODE (arg1) == SSA_NAME) | |
458 | { | |
459 | /* Check if arg1 is an SSA_NAME and the stmt which defines arg1 | |
460 | is a conversion. */ | |
461 | arg1_def_stmt = SSA_NAME_DEF_STMT (arg1); | |
462 | if (!is_gimple_assign (arg1_def_stmt) | |
463 | || gimple_assign_rhs_code (arg1_def_stmt) != convert_code) | |
5dccd071 | 464 | return NULL; |
29a78fec | 465 | |
466 | /* Use the RHS as new_arg1. */ | |
467 | new_arg1 = gimple_assign_rhs1 (arg1_def_stmt); | |
468 | if (convert_code == VIEW_CONVERT_EXPR) | |
469 | new_arg1 = TREE_OPERAND (new_arg1, 0); | |
470 | } | |
471 | else | |
472 | { | |
473 | /* If arg1 is an INTEGER_CST, fold it to new type. */ | |
474 | if (INTEGRAL_TYPE_P (TREE_TYPE (new_arg0)) | |
475 | && int_fits_type_p (arg1, TREE_TYPE (new_arg0))) | |
476 | { | |
477 | if (gimple_assign_cast_p (arg0_def_stmt)) | |
8100256d | 478 | { |
479 | /* For the INTEGER_CST case, we are just moving the | |
480 | conversion from one place to another, which can often | |
481 | hurt as the conversion moves further away from the | |
482 | statement that computes the value. So, perform this | |
483 | only if new_arg0 is an operand of COND_STMT, or | |
484 | if arg0_def_stmt is the only non-debug stmt in | |
485 | its basic block, because then it is possible this | |
486 | could enable further optimizations (minmax replacement | |
487 | etc.). See PR71016. */ | |
488 | if (new_arg0 != gimple_cond_lhs (cond_stmt) | |
489 | && new_arg0 != gimple_cond_rhs (cond_stmt) | |
490 | && gimple_bb (arg0_def_stmt) == e0->src) | |
491 | { | |
492 | gsi = gsi_for_stmt (arg0_def_stmt); | |
493 | gsi_prev_nondebug (&gsi); | |
494 | if (!gsi_end_p (gsi)) | |
495 | return NULL; | |
496 | gsi = gsi_for_stmt (arg0_def_stmt); | |
497 | gsi_next_nondebug (&gsi); | |
498 | if (!gsi_end_p (gsi)) | |
499 | return NULL; | |
500 | } | |
501 | new_arg1 = fold_convert (TREE_TYPE (new_arg0), arg1); | |
502 | } | |
29a78fec | 503 | else |
5dccd071 | 504 | return NULL; |
29a78fec | 505 | } |
506 | else | |
5dccd071 | 507 | return NULL; |
29a78fec | 508 | } |
509 | ||
510 | /* If arg0/arg1 have > 1 use, then this transformation actually increases | |
511 | the number of expressions evaluated at runtime. */ | |
512 | if (!has_single_use (arg0) | |
513 | || (arg1_def_stmt && !has_single_use (arg1))) | |
5dccd071 | 514 | return NULL; |
29a78fec | 515 | |
516 | /* If types of new_arg0 and new_arg1 are different bailout. */ | |
517 | if (!types_compatible_p (TREE_TYPE (new_arg0), TREE_TYPE (new_arg1))) | |
5dccd071 | 518 | return NULL; |
29a78fec | 519 | |
520 | /* Create a new PHI stmt. */ | |
521 | result = PHI_RESULT (phi); | |
522 | temp = make_ssa_name (TREE_TYPE (new_arg0), NULL); | |
523 | newphi = create_phi_node (temp, gimple_bb (phi)); | |
524 | ||
525 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
526 | { | |
527 | fprintf (dump_file, "PHI "); | |
1ffa4346 | 528 | print_generic_expr (dump_file, gimple_phi_result (phi)); |
29a78fec | 529 | fprintf (dump_file, |
530 | " changed to factor conversion out from COND_EXPR.\n"); | |
531 | fprintf (dump_file, "New stmt with CAST that defines "); | |
1ffa4346 | 532 | print_generic_expr (dump_file, result); |
29a78fec | 533 | fprintf (dump_file, ".\n"); |
534 | } | |
535 | ||
536 | /* Remove the old cast(s) that has single use. */ | |
537 | gsi_for_def = gsi_for_stmt (arg0_def_stmt); | |
538 | gsi_remove (&gsi_for_def, true); | |
3f6d43bf | 539 | release_defs (arg0_def_stmt); |
540 | ||
29a78fec | 541 | if (arg1_def_stmt) |
542 | { | |
543 | gsi_for_def = gsi_for_stmt (arg1_def_stmt); | |
544 | gsi_remove (&gsi_for_def, true); | |
3f6d43bf | 545 | release_defs (arg1_def_stmt); |
29a78fec | 546 | } |
547 | ||
548 | add_phi_arg (newphi, new_arg0, e0, locus); | |
549 | add_phi_arg (newphi, new_arg1, e1, locus); | |
550 | ||
551 | /* Create the conversion stmt and insert it. */ | |
552 | if (convert_code == VIEW_CONVERT_EXPR) | |
553 | temp = fold_build1 (VIEW_CONVERT_EXPR, TREE_TYPE (result), temp); | |
8100256d | 554 | new_stmt = gimple_build_assign (result, convert_code, temp); |
29a78fec | 555 | gsi = gsi_after_labels (gimple_bb (phi)); |
556 | gsi_insert_before (&gsi, new_stmt, GSI_SAME_STMT); | |
557 | ||
3f6d43bf | 558 | /* Remove the original PHI stmt. */ |
29a78fec | 559 | gsi = gsi_for_stmt (phi); |
560 | gsi_remove (&gsi, true); | |
5dccd071 | 561 | return newphi; |
29a78fec | 562 | } |
563 | ||
902929aa | 564 | /* The function conditional_replacement does the main work of doing the |
565 | conditional replacement. Return true if the replacement is done. | |
566 | Otherwise return false. | |
567 | BB is the basic block where the replacement is going to be done on. ARG0 | |
dac49aa5 | 568 | is argument 0 from PHI. Likewise for ARG1. */ |
902929aa | 569 | |
570 | static bool | |
33784d89 | 571 | conditional_replacement (basic_block cond_bb, basic_block middle_bb, |
1a91d914 | 572 | edge e0, edge e1, gphi *phi, |
33784d89 | 573 | tree arg0, tree arg1) |
902929aa | 574 | { |
575 | tree result; | |
42acab1c | 576 | gimple *stmt; |
1a91d914 | 577 | gassign *new_stmt; |
75a70cf9 | 578 | tree cond; |
579 | gimple_stmt_iterator gsi; | |
902929aa | 580 | edge true_edge, false_edge; |
75a70cf9 | 581 | tree new_var, new_var2; |
678919fd | 582 | bool neg; |
902929aa | 583 | |
435e1a75 | 584 | /* FIXME: Gimplification of complex type is too hard for now. */ |
47b88316 | 585 | /* We aren't prepared to handle vectors either (and it is a question |
586 | if it would be worthwhile anyway). */ | |
587 | if (!(INTEGRAL_TYPE_P (TREE_TYPE (arg0)) | |
588 | || POINTER_TYPE_P (TREE_TYPE (arg0))) | |
589 | || !(INTEGRAL_TYPE_P (TREE_TYPE (arg1)) | |
590 | || POINTER_TYPE_P (TREE_TYPE (arg1)))) | |
435e1a75 | 591 | return false; |
592 | ||
678919fd | 593 | /* The PHI arguments have the constants 0 and 1, or 0 and -1, then |
594 | convert it to the conditional. */ | |
902929aa | 595 | if ((integer_zerop (arg0) && integer_onep (arg1)) |
596 | || (integer_zerop (arg1) && integer_onep (arg0))) | |
678919fd | 597 | neg = false; |
598 | else if ((integer_zerop (arg0) && integer_all_onesp (arg1)) | |
599 | || (integer_zerop (arg1) && integer_all_onesp (arg0))) | |
600 | neg = true; | |
902929aa | 601 | else |
602 | return false; | |
20e5647c | 603 | |
33784d89 | 604 | if (!empty_block_p (middle_bb)) |
902929aa | 605 | return false; |
20e5647c | 606 | |
75a70cf9 | 607 | /* At this point we know we have a GIMPLE_COND with two successors. |
2ab0a163 | 608 | One successor is BB, the other successor is an empty block which |
609 | falls through into BB. | |
20e5647c | 610 | |
2ab0a163 | 611 | There is a single PHI node at the join point (BB) and its arguments |
678919fd | 612 | are constants (0, 1) or (0, -1). |
20e5647c | 613 | |
2ab0a163 | 614 | So, given the condition COND, and the two PHI arguments, we can |
20e5647c | 615 | rewrite this PHI into non-branching code: |
616 | ||
2ab0a163 | 617 | dest = (COND) or dest = COND' |
20e5647c | 618 | |
2ab0a163 | 619 | We use the condition as-is if the argument associated with the |
620 | true edge has the value one or the argument associated with the | |
621 | false edge as the value zero. Note that those conditions are not | |
75a70cf9 | 622 | the same since only one of the outgoing edges from the GIMPLE_COND |
2ab0a163 | 623 | will directly reach BB and thus be associated with an argument. */ |
ae5a4794 | 624 | |
75a70cf9 | 625 | stmt = last_stmt (cond_bb); |
626 | result = PHI_RESULT (phi); | |
b2a02a0e | 627 | |
75a70cf9 | 628 | /* To handle special cases like floating point comparison, it is easier and |
629 | less error-prone to build a tree and gimplify it on the fly though it is | |
630 | less efficient. */ | |
6f9714b3 | 631 | cond = fold_build2_loc (gimple_location (stmt), |
632 | gimple_cond_code (stmt), boolean_type_node, | |
633 | gimple_cond_lhs (stmt), gimple_cond_rhs (stmt)); | |
4ee9c684 | 634 | |
75a70cf9 | 635 | /* We need to know which is the true edge and which is the false |
636 | edge so that we know when to invert the condition below. */ | |
637 | extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge); | |
638 | if ((e0 == true_edge && integer_zerop (arg0)) | |
678919fd | 639 | || (e0 == false_edge && !integer_zerop (arg0)) |
75a70cf9 | 640 | || (e1 == true_edge && integer_zerop (arg1)) |
678919fd | 641 | || (e1 == false_edge && !integer_zerop (arg1))) |
6f9714b3 | 642 | cond = fold_build1_loc (gimple_location (stmt), |
678919fd | 643 | TRUTH_NOT_EXPR, TREE_TYPE (cond), cond); |
644 | ||
645 | if (neg) | |
646 | { | |
647 | cond = fold_convert_loc (gimple_location (stmt), | |
648 | TREE_TYPE (result), cond); | |
649 | cond = fold_build1_loc (gimple_location (stmt), | |
650 | NEGATE_EXPR, TREE_TYPE (cond), cond); | |
651 | } | |
75a70cf9 | 652 | |
653 | /* Insert our new statements at the end of conditional block before the | |
654 | COND_STMT. */ | |
655 | gsi = gsi_for_stmt (stmt); | |
656 | new_var = force_gimple_operand_gsi (&gsi, cond, true, NULL, true, | |
657 | GSI_SAME_STMT); | |
658 | ||
659 | if (!useless_type_conversion_p (TREE_TYPE (result), TREE_TYPE (new_var))) | |
660 | { | |
efbcb6de | 661 | source_location locus_0, locus_1; |
662 | ||
f9e245b2 | 663 | new_var2 = make_ssa_name (TREE_TYPE (result)); |
e9cf809e | 664 | new_stmt = gimple_build_assign (new_var2, CONVERT_EXPR, new_var); |
75a70cf9 | 665 | gsi_insert_before (&gsi, new_stmt, GSI_SAME_STMT); |
666 | new_var = new_var2; | |
efbcb6de | 667 | |
668 | /* Set the locus to the first argument, unless is doesn't have one. */ | |
669 | locus_0 = gimple_phi_arg_location (phi, 0); | |
670 | locus_1 = gimple_phi_arg_location (phi, 1); | |
671 | if (locus_0 == UNKNOWN_LOCATION) | |
672 | locus_0 = locus_1; | |
673 | gimple_set_location (new_stmt, locus_0); | |
4ee9c684 | 674 | } |
20e5647c | 675 | |
75a70cf9 | 676 | replace_phi_edge_with_variable (cond_bb, e1, phi, new_var); |
8c1ab18f | 677 | reset_flow_sensitive_info_in_bb (cond_bb); |
902929aa | 678 | |
4ee9c684 | 679 | /* Note that we optimized this PHI. */ |
680 | return true; | |
681 | } | |
682 | ||
17b9476e | 683 | /* Update *ARG which is defined in STMT so that it contains the |
684 | computed value if that seems profitable. Return true if the | |
685 | statement is made dead by that rewriting. */ | |
686 | ||
687 | static bool | |
42acab1c | 688 | jump_function_from_stmt (tree *arg, gimple *stmt) |
17b9476e | 689 | { |
690 | enum tree_code code = gimple_assign_rhs_code (stmt); | |
691 | if (code == ADDR_EXPR) | |
692 | { | |
693 | /* For arg = &p->i transform it to p, if possible. */ | |
694 | tree rhs1 = gimple_assign_rhs1 (stmt); | |
695 | HOST_WIDE_INT offset; | |
696 | tree tem = get_addr_base_and_unit_offset (TREE_OPERAND (rhs1, 0), | |
697 | &offset); | |
698 | if (tem | |
699 | && TREE_CODE (tem) == MEM_REF | |
796b6678 | 700 | && (mem_ref_offset (tem) + offset) == 0) |
17b9476e | 701 | { |
702 | *arg = TREE_OPERAND (tem, 0); | |
703 | return true; | |
704 | } | |
705 | } | |
706 | /* TODO: Much like IPA-CP jump-functions we want to handle constant | |
707 | additions symbolically here, and we'd need to update the comparison | |
708 | code that compares the arg + cst tuples in our caller. For now the | |
709 | code above exactly handles the VEC_BASE pattern from vec.h. */ | |
710 | return false; | |
711 | } | |
712 | ||
f32420fb | 713 | /* RHS is a source argument in a BIT_AND_EXPR which feeds a conditional |
714 | of the form SSA_NAME NE 0. | |
715 | ||
716 | If RHS is fed by a simple EQ_EXPR comparison of two values, see if | |
717 | the two input values of the EQ_EXPR match arg0 and arg1. | |
718 | ||
719 | If so update *code and return TRUE. Otherwise return FALSE. */ | |
720 | ||
721 | static bool | |
722 | rhs_is_fed_for_value_replacement (const_tree arg0, const_tree arg1, | |
723 | enum tree_code *code, const_tree rhs) | |
724 | { | |
725 | /* Obviously if RHS is not an SSA_NAME, we can't look at the defining | |
726 | statement. */ | |
727 | if (TREE_CODE (rhs) == SSA_NAME) | |
728 | { | |
42acab1c | 729 | gimple *def1 = SSA_NAME_DEF_STMT (rhs); |
f32420fb | 730 | |
731 | /* Verify the defining statement has an EQ_EXPR on the RHS. */ | |
732 | if (is_gimple_assign (def1) && gimple_assign_rhs_code (def1) == EQ_EXPR) | |
733 | { | |
734 | /* Finally verify the source operands of the EQ_EXPR are equal | |
735 | to arg0 and arg1. */ | |
736 | tree op0 = gimple_assign_rhs1 (def1); | |
737 | tree op1 = gimple_assign_rhs2 (def1); | |
738 | if ((operand_equal_for_phi_arg_p (arg0, op0) | |
739 | && operand_equal_for_phi_arg_p (arg1, op1)) | |
740 | || (operand_equal_for_phi_arg_p (arg0, op1) | |
741 | && operand_equal_for_phi_arg_p (arg1, op0))) | |
742 | { | |
743 | /* We will perform the optimization. */ | |
744 | *code = gimple_assign_rhs_code (def1); | |
745 | return true; | |
746 | } | |
747 | } | |
748 | } | |
749 | return false; | |
750 | } | |
751 | ||
752 | /* Return TRUE if arg0/arg1 are equal to the rhs/lhs or lhs/rhs of COND. | |
753 | ||
754 | Also return TRUE if arg0/arg1 are equal to the source arguments of a | |
755 | an EQ comparison feeding a BIT_AND_EXPR which feeds COND. | |
756 | ||
757 | Return FALSE otherwise. */ | |
758 | ||
759 | static bool | |
760 | operand_equal_for_value_replacement (const_tree arg0, const_tree arg1, | |
42acab1c | 761 | enum tree_code *code, gimple *cond) |
f32420fb | 762 | { |
42acab1c | 763 | gimple *def; |
f32420fb | 764 | tree lhs = gimple_cond_lhs (cond); |
765 | tree rhs = gimple_cond_rhs (cond); | |
766 | ||
767 | if ((operand_equal_for_phi_arg_p (arg0, lhs) | |
768 | && operand_equal_for_phi_arg_p (arg1, rhs)) | |
769 | || (operand_equal_for_phi_arg_p (arg1, lhs) | |
770 | && operand_equal_for_phi_arg_p (arg0, rhs))) | |
771 | return true; | |
772 | ||
773 | /* Now handle more complex case where we have an EQ comparison | |
774 | which feeds a BIT_AND_EXPR which feeds COND. | |
775 | ||
776 | First verify that COND is of the form SSA_NAME NE 0. */ | |
777 | if (*code != NE_EXPR || !integer_zerop (rhs) | |
778 | || TREE_CODE (lhs) != SSA_NAME) | |
779 | return false; | |
780 | ||
781 | /* Now ensure that SSA_NAME is set by a BIT_AND_EXPR. */ | |
782 | def = SSA_NAME_DEF_STMT (lhs); | |
783 | if (!is_gimple_assign (def) || gimple_assign_rhs_code (def) != BIT_AND_EXPR) | |
784 | return false; | |
785 | ||
786 | /* Now verify arg0/arg1 correspond to the source arguments of an | |
787 | EQ comparison feeding the BIT_AND_EXPR. */ | |
788 | ||
789 | tree tmp = gimple_assign_rhs1 (def); | |
790 | if (rhs_is_fed_for_value_replacement (arg0, arg1, code, tmp)) | |
791 | return true; | |
792 | ||
793 | tmp = gimple_assign_rhs2 (def); | |
794 | if (rhs_is_fed_for_value_replacement (arg0, arg1, code, tmp)) | |
795 | return true; | |
796 | ||
797 | return false; | |
798 | } | |
799 | ||
b6814ca0 | 800 | /* Returns true if ARG is a neutral element for operation CODE |
801 | on the RIGHT side. */ | |
802 | ||
803 | static bool | |
804 | neutral_element_p (tree_code code, tree arg, bool right) | |
805 | { | |
806 | switch (code) | |
807 | { | |
808 | case PLUS_EXPR: | |
809 | case BIT_IOR_EXPR: | |
810 | case BIT_XOR_EXPR: | |
811 | return integer_zerop (arg); | |
812 | ||
813 | case LROTATE_EXPR: | |
814 | case RROTATE_EXPR: | |
815 | case LSHIFT_EXPR: | |
816 | case RSHIFT_EXPR: | |
817 | case MINUS_EXPR: | |
818 | case POINTER_PLUS_EXPR: | |
819 | return right && integer_zerop (arg); | |
820 | ||
821 | case MULT_EXPR: | |
822 | return integer_onep (arg); | |
823 | ||
824 | case TRUNC_DIV_EXPR: | |
825 | case CEIL_DIV_EXPR: | |
826 | case FLOOR_DIV_EXPR: | |
827 | case ROUND_DIV_EXPR: | |
828 | case EXACT_DIV_EXPR: | |
829 | return right && integer_onep (arg); | |
830 | ||
831 | case BIT_AND_EXPR: | |
832 | return integer_all_onesp (arg); | |
833 | ||
834 | default: | |
835 | return false; | |
836 | } | |
837 | } | |
838 | ||
839 | /* Returns true if ARG is an absorbing element for operation CODE. */ | |
840 | ||
841 | static bool | |
2177bb9a | 842 | absorbing_element_p (tree_code code, tree arg, bool right, tree rval) |
b6814ca0 | 843 | { |
844 | switch (code) | |
845 | { | |
846 | case BIT_IOR_EXPR: | |
847 | return integer_all_onesp (arg); | |
848 | ||
849 | case MULT_EXPR: | |
850 | case BIT_AND_EXPR: | |
851 | return integer_zerop (arg); | |
852 | ||
0644c120 | 853 | case LSHIFT_EXPR: |
854 | case RSHIFT_EXPR: | |
855 | case LROTATE_EXPR: | |
856 | case RROTATE_EXPR: | |
2177bb9a | 857 | return !right && integer_zerop (arg); |
858 | ||
0644c120 | 859 | case TRUNC_DIV_EXPR: |
860 | case CEIL_DIV_EXPR: | |
861 | case FLOOR_DIV_EXPR: | |
862 | case ROUND_DIV_EXPR: | |
863 | case EXACT_DIV_EXPR: | |
864 | case TRUNC_MOD_EXPR: | |
865 | case CEIL_MOD_EXPR: | |
866 | case FLOOR_MOD_EXPR: | |
867 | case ROUND_MOD_EXPR: | |
2177bb9a | 868 | return (!right |
869 | && integer_zerop (arg) | |
870 | && tree_single_nonzero_warnv_p (rval, NULL)); | |
0644c120 | 871 | |
b6814ca0 | 872 | default: |
873 | return false; | |
874 | } | |
875 | } | |
876 | ||
0beac6fc | 877 | /* The function value_replacement does the main work of doing the value |
fb9912ea | 878 | replacement. Return non-zero if the replacement is done. Otherwise return |
879 | 0. If we remove the middle basic block, return 2. | |
0beac6fc | 880 | BB is the basic block where the replacement is going to be done on. ARG0 |
dac49aa5 | 881 | is argument 0 from the PHI. Likewise for ARG1. */ |
0beac6fc | 882 | |
fb9912ea | 883 | static int |
33784d89 | 884 | value_replacement (basic_block cond_bb, basic_block middle_bb, |
42acab1c | 885 | edge e0, edge e1, gimple *phi, |
33784d89 | 886 | tree arg0, tree arg1) |
0beac6fc | 887 | { |
17b9476e | 888 | gimple_stmt_iterator gsi; |
42acab1c | 889 | gimple *cond; |
0beac6fc | 890 | edge true_edge, false_edge; |
75a70cf9 | 891 | enum tree_code code; |
fb9912ea | 892 | bool emtpy_or_with_defined_p = true; |
0beac6fc | 893 | |
894 | /* If the type says honor signed zeros we cannot do this | |
dac49aa5 | 895 | optimization. */ |
fe994837 | 896 | if (HONOR_SIGNED_ZEROS (arg1)) |
fb9912ea | 897 | return 0; |
0beac6fc | 898 | |
fb9912ea | 899 | /* If there is a statement in MIDDLE_BB that defines one of the PHI |
900 | arguments, then adjust arg0 or arg1. */ | |
b6814ca0 | 901 | gsi = gsi_start_nondebug_after_labels_bb (middle_bb); |
fb9912ea | 902 | while (!gsi_end_p (gsi)) |
17b9476e | 903 | { |
42acab1c | 904 | gimple *stmt = gsi_stmt (gsi); |
fb9912ea | 905 | tree lhs; |
906 | gsi_next_nondebug (&gsi); | |
907 | if (!is_gimple_assign (stmt)) | |
17b9476e | 908 | { |
fb9912ea | 909 | emtpy_or_with_defined_p = false; |
910 | continue; | |
17b9476e | 911 | } |
fb9912ea | 912 | /* Now try to adjust arg0 or arg1 according to the computation |
913 | in the statement. */ | |
914 | lhs = gimple_assign_lhs (stmt); | |
915 | if (!(lhs == arg0 | |
916 | && jump_function_from_stmt (&arg0, stmt)) | |
917 | || (lhs == arg1 | |
918 | && jump_function_from_stmt (&arg1, stmt))) | |
919 | emtpy_or_with_defined_p = false; | |
17b9476e | 920 | } |
0beac6fc | 921 | |
75a70cf9 | 922 | cond = last_stmt (cond_bb); |
923 | code = gimple_cond_code (cond); | |
0beac6fc | 924 | |
925 | /* This transformation is only valid for equality comparisons. */ | |
75a70cf9 | 926 | if (code != NE_EXPR && code != EQ_EXPR) |
fb9912ea | 927 | return 0; |
0beac6fc | 928 | |
929 | /* We need to know which is the true edge and which is the false | |
930 | edge so that we know if have abs or negative abs. */ | |
33784d89 | 931 | extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge); |
0beac6fc | 932 | |
933 | /* At this point we know we have a COND_EXPR with two successors. | |
934 | One successor is BB, the other successor is an empty block which | |
935 | falls through into BB. | |
936 | ||
937 | The condition for the COND_EXPR is known to be NE_EXPR or EQ_EXPR. | |
938 | ||
939 | There is a single PHI node at the join point (BB) with two arguments. | |
940 | ||
941 | We now need to verify that the two arguments in the PHI node match | |
942 | the two arguments to the equality comparison. */ | |
20e5647c | 943 | |
f32420fb | 944 | if (operand_equal_for_value_replacement (arg0, arg1, &code, cond)) |
0beac6fc | 945 | { |
946 | edge e; | |
947 | tree arg; | |
948 | ||
50737d20 | 949 | /* For NE_EXPR, we want to build an assignment result = arg where |
950 | arg is the PHI argument associated with the true edge. For | |
951 | EQ_EXPR we want the PHI argument associated with the false edge. */ | |
75a70cf9 | 952 | e = (code == NE_EXPR ? true_edge : false_edge); |
50737d20 | 953 | |
954 | /* Unfortunately, E may not reach BB (it may instead have gone to | |
955 | OTHER_BLOCK). If that is the case, then we want the single outgoing | |
956 | edge from OTHER_BLOCK which reaches BB and represents the desired | |
957 | path from COND_BLOCK. */ | |
33784d89 | 958 | if (e->dest == middle_bb) |
ea091dfd | 959 | e = single_succ_edge (e->dest); |
50737d20 | 960 | |
961 | /* Now we know the incoming edge to BB that has the argument for the | |
962 | RHS of our new assignment statement. */ | |
33784d89 | 963 | if (e0 == e) |
0beac6fc | 964 | arg = arg0; |
965 | else | |
966 | arg = arg1; | |
967 | ||
fb9912ea | 968 | /* If the middle basic block was empty or is defining the |
c3597b05 | 969 | PHI arguments and this is a single phi where the args are different |
970 | for the edges e0 and e1 then we can remove the middle basic block. */ | |
fb9912ea | 971 | if (emtpy_or_with_defined_p |
c3597b05 | 972 | && single_non_singleton_phi_for_edges (phi_nodes (gimple_bb (phi)), |
ce75c7c2 | 973 | e0, e1) == phi) |
fb9912ea | 974 | { |
975 | replace_phi_edge_with_variable (cond_bb, e1, phi, arg); | |
976 | /* Note that we optimized this PHI. */ | |
977 | return 2; | |
978 | } | |
979 | else | |
980 | { | |
981 | /* Replace the PHI arguments with arg. */ | |
982 | SET_PHI_ARG_DEF (phi, e0->dest_idx, arg); | |
983 | SET_PHI_ARG_DEF (phi, e1->dest_idx, arg); | |
984 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
985 | { | |
986 | fprintf (dump_file, "PHI "); | |
1ffa4346 | 987 | print_generic_expr (dump_file, gimple_phi_result (phi)); |
c3597b05 | 988 | fprintf (dump_file, " reduced for COND_EXPR in block %d to ", |
989 | cond_bb->index); | |
1ffa4346 | 990 | print_generic_expr (dump_file, arg); |
fb9912ea | 991 | fprintf (dump_file, ".\n"); |
992 | } | |
993 | return 1; | |
994 | } | |
0beac6fc | 995 | |
0beac6fc | 996 | } |
b6814ca0 | 997 | |
998 | /* Now optimize (x != 0) ? x + y : y to just y. | |
999 | The following condition is too restrictive, there can easily be another | |
1000 | stmt in middle_bb, for instance a CONVERT_EXPR for the second argument. */ | |
42acab1c | 1001 | gimple *assign = last_and_only_stmt (middle_bb); |
b6814ca0 | 1002 | if (!assign || gimple_code (assign) != GIMPLE_ASSIGN |
1003 | || gimple_assign_rhs_class (assign) != GIMPLE_BINARY_RHS | |
1004 | || (!INTEGRAL_TYPE_P (TREE_TYPE (arg0)) | |
1005 | && !POINTER_TYPE_P (TREE_TYPE (arg0)))) | |
1006 | return 0; | |
1007 | ||
6c96fe34 | 1008 | /* Punt if there are (degenerate) PHIs in middle_bb, there should not be. */ |
1009 | if (!gimple_seq_empty_p (phi_nodes (middle_bb))) | |
1010 | return 0; | |
1011 | ||
43fbec4a | 1012 | /* Only transform if it removes the condition. */ |
1013 | if (!single_non_singleton_phi_for_edges (phi_nodes (gimple_bb (phi)), e0, e1)) | |
1014 | return 0; | |
1015 | ||
b6814ca0 | 1016 | /* Size-wise, this is always profitable. */ |
1017 | if (optimize_bb_for_speed_p (cond_bb) | |
1018 | /* The special case is useless if it has a low probability. */ | |
1019 | && profile_status_for_fn (cfun) != PROFILE_ABSENT | |
720cfc43 | 1020 | && EDGE_PRED (middle_bb, 0)->probability < profile_probability::even () |
b6814ca0 | 1021 | /* If assign is cheap, there is no point avoiding it. */ |
1022 | && estimate_num_insns (assign, &eni_time_weights) | |
1023 | >= 3 * estimate_num_insns (cond, &eni_time_weights)) | |
1024 | return 0; | |
1025 | ||
1026 | tree lhs = gimple_assign_lhs (assign); | |
1027 | tree rhs1 = gimple_assign_rhs1 (assign); | |
1028 | tree rhs2 = gimple_assign_rhs2 (assign); | |
1029 | enum tree_code code_def = gimple_assign_rhs_code (assign); | |
1030 | tree cond_lhs = gimple_cond_lhs (cond); | |
1031 | tree cond_rhs = gimple_cond_rhs (cond); | |
1032 | ||
1033 | if (((code == NE_EXPR && e1 == false_edge) | |
1034 | || (code == EQ_EXPR && e1 == true_edge)) | |
1035 | && arg0 == lhs | |
1036 | && ((arg1 == rhs1 | |
1037 | && operand_equal_for_phi_arg_p (rhs2, cond_lhs) | |
1038 | && neutral_element_p (code_def, cond_rhs, true)) | |
1039 | || (arg1 == rhs2 | |
1040 | && operand_equal_for_phi_arg_p (rhs1, cond_lhs) | |
1041 | && neutral_element_p (code_def, cond_rhs, false)) | |
1042 | || (operand_equal_for_phi_arg_p (arg1, cond_rhs) | |
0644c120 | 1043 | && ((operand_equal_for_phi_arg_p (rhs2, cond_lhs) |
2177bb9a | 1044 | && absorbing_element_p (code_def, cond_rhs, true, rhs2)) |
0644c120 | 1045 | || (operand_equal_for_phi_arg_p (rhs1, cond_lhs) |
2177bb9a | 1046 | && absorbing_element_p (code_def, |
1047 | cond_rhs, false, rhs2)))))) | |
b6814ca0 | 1048 | { |
1049 | gsi = gsi_for_stmt (cond); | |
18c06fb8 | 1050 | if (INTEGRAL_TYPE_P (TREE_TYPE (lhs))) |
1051 | { | |
1052 | /* Moving ASSIGN might change VR of lhs, e.g. when moving u_6 | |
1053 | def-stmt in: | |
1054 | if (n_5 != 0) | |
1055 | goto <bb 3>; | |
1056 | else | |
1057 | goto <bb 4>; | |
1058 | ||
1059 | <bb 3>: | |
1060 | # RANGE [0, 4294967294] | |
1061 | u_6 = n_5 + 4294967295; | |
1062 | ||
1063 | <bb 4>: | |
1064 | # u_3 = PHI <u_6(3), 4294967295(2)> */ | |
1065 | SSA_NAME_RANGE_INFO (lhs) = NULL; | |
18c06fb8 | 1066 | /* If available, we can use VR of phi result at least. */ |
1067 | tree phires = gimple_phi_result (phi); | |
1068 | struct range_info_def *phires_range_info | |
1069 | = SSA_NAME_RANGE_INFO (phires); | |
1070 | if (phires_range_info) | |
1071 | duplicate_ssa_name_range_info (lhs, SSA_NAME_RANGE_TYPE (phires), | |
1072 | phires_range_info); | |
1073 | } | |
b6814ca0 | 1074 | gimple_stmt_iterator gsi_from = gsi_for_stmt (assign); |
1075 | gsi_move_before (&gsi_from, &gsi); | |
1076 | replace_phi_edge_with_variable (cond_bb, e1, phi, lhs); | |
1077 | return 2; | |
1078 | } | |
1079 | ||
fb9912ea | 1080 | return 0; |
0beac6fc | 1081 | } |
1082 | ||
194899bf | 1083 | /* The function minmax_replacement does the main work of doing the minmax |
1084 | replacement. Return true if the replacement is done. Otherwise return | |
1085 | false. | |
1086 | BB is the basic block where the replacement is going to be done on. ARG0 | |
1087 | is argument 0 from the PHI. Likewise for ARG1. */ | |
1088 | ||
1089 | static bool | |
1090 | minmax_replacement (basic_block cond_bb, basic_block middle_bb, | |
42acab1c | 1091 | edge e0, edge e1, gimple *phi, |
194899bf | 1092 | tree arg0, tree arg1) |
1093 | { | |
1094 | tree result, type; | |
1a91d914 | 1095 | gcond *cond; |
1096 | gassign *new_stmt; | |
194899bf | 1097 | edge true_edge, false_edge; |
1098 | enum tree_code cmp, minmax, ass_code; | |
74201dc2 | 1099 | tree smaller, alt_smaller, larger, alt_larger, arg_true, arg_false; |
75a70cf9 | 1100 | gimple_stmt_iterator gsi, gsi_from; |
194899bf | 1101 | |
1102 | type = TREE_TYPE (PHI_RESULT (phi)); | |
1103 | ||
1104 | /* The optimization may be unsafe due to NaNs. */ | |
b0ab3ca0 | 1105 | if (HONOR_NANS (type) || HONOR_SIGNED_ZEROS (type)) |
194899bf | 1106 | return false; |
1107 | ||
1a91d914 | 1108 | cond = as_a <gcond *> (last_stmt (cond_bb)); |
75a70cf9 | 1109 | cmp = gimple_cond_code (cond); |
194899bf | 1110 | |
1111 | /* This transformation is only valid for order comparisons. Record which | |
1112 | operand is smaller/larger if the result of the comparison is true. */ | |
74201dc2 | 1113 | alt_smaller = NULL_TREE; |
1114 | alt_larger = NULL_TREE; | |
194899bf | 1115 | if (cmp == LT_EXPR || cmp == LE_EXPR) |
1116 | { | |
75a70cf9 | 1117 | smaller = gimple_cond_lhs (cond); |
1118 | larger = gimple_cond_rhs (cond); | |
74201dc2 | 1119 | /* If we have smaller < CST it is equivalent to smaller <= CST-1. |
1120 | Likewise smaller <= CST is equivalent to smaller < CST+1. */ | |
1121 | if (TREE_CODE (larger) == INTEGER_CST) | |
1122 | { | |
1123 | if (cmp == LT_EXPR) | |
1124 | { | |
1125 | bool overflow; | |
1126 | wide_int alt = wi::sub (larger, 1, TYPE_SIGN (TREE_TYPE (larger)), | |
1127 | &overflow); | |
1128 | if (! overflow) | |
1129 | alt_larger = wide_int_to_tree (TREE_TYPE (larger), alt); | |
1130 | } | |
1131 | else | |
1132 | { | |
1133 | bool overflow; | |
1134 | wide_int alt = wi::add (larger, 1, TYPE_SIGN (TREE_TYPE (larger)), | |
1135 | &overflow); | |
1136 | if (! overflow) | |
1137 | alt_larger = wide_int_to_tree (TREE_TYPE (larger), alt); | |
1138 | } | |
1139 | } | |
194899bf | 1140 | } |
1141 | else if (cmp == GT_EXPR || cmp == GE_EXPR) | |
1142 | { | |
75a70cf9 | 1143 | smaller = gimple_cond_rhs (cond); |
1144 | larger = gimple_cond_lhs (cond); | |
74201dc2 | 1145 | /* If we have larger > CST it is equivalent to larger >= CST+1. |
1146 | Likewise larger >= CST is equivalent to larger > CST-1. */ | |
1147 | if (TREE_CODE (smaller) == INTEGER_CST) | |
1148 | { | |
1149 | if (cmp == GT_EXPR) | |
1150 | { | |
1151 | bool overflow; | |
1152 | wide_int alt = wi::add (smaller, 1, TYPE_SIGN (TREE_TYPE (smaller)), | |
1153 | &overflow); | |
1154 | if (! overflow) | |
1155 | alt_smaller = wide_int_to_tree (TREE_TYPE (smaller), alt); | |
1156 | } | |
1157 | else | |
1158 | { | |
1159 | bool overflow; | |
1160 | wide_int alt = wi::sub (smaller, 1, TYPE_SIGN (TREE_TYPE (smaller)), | |
1161 | &overflow); | |
1162 | if (! overflow) | |
1163 | alt_smaller = wide_int_to_tree (TREE_TYPE (smaller), alt); | |
1164 | } | |
1165 | } | |
194899bf | 1166 | } |
1167 | else | |
1168 | return false; | |
1169 | ||
1170 | /* We need to know which is the true edge and which is the false | |
1171 | edge so that we know if have abs or negative abs. */ | |
1172 | extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge); | |
1173 | ||
1174 | /* Forward the edges over the middle basic block. */ | |
1175 | if (true_edge->dest == middle_bb) | |
1176 | true_edge = EDGE_SUCC (true_edge->dest, 0); | |
1177 | if (false_edge->dest == middle_bb) | |
1178 | false_edge = EDGE_SUCC (false_edge->dest, 0); | |
1179 | ||
1180 | if (true_edge == e0) | |
1181 | { | |
1182 | gcc_assert (false_edge == e1); | |
1183 | arg_true = arg0; | |
1184 | arg_false = arg1; | |
1185 | } | |
1186 | else | |
1187 | { | |
1188 | gcc_assert (false_edge == e0); | |
1189 | gcc_assert (true_edge == e1); | |
1190 | arg_true = arg1; | |
1191 | arg_false = arg0; | |
1192 | } | |
1193 | ||
1194 | if (empty_block_p (middle_bb)) | |
1195 | { | |
74201dc2 | 1196 | if ((operand_equal_for_phi_arg_p (arg_true, smaller) |
1197 | || (alt_smaller | |
1198 | && operand_equal_for_phi_arg_p (arg_true, alt_smaller))) | |
1199 | && (operand_equal_for_phi_arg_p (arg_false, larger) | |
1200 | || (alt_larger | |
1201 | && operand_equal_for_phi_arg_p (arg_true, alt_larger)))) | |
194899bf | 1202 | { |
1203 | /* Case | |
48e1416a | 1204 | |
194899bf | 1205 | if (smaller < larger) |
1206 | rslt = smaller; | |
1207 | else | |
1208 | rslt = larger; */ | |
1209 | minmax = MIN_EXPR; | |
1210 | } | |
74201dc2 | 1211 | else if ((operand_equal_for_phi_arg_p (arg_false, smaller) |
1212 | || (alt_smaller | |
1213 | && operand_equal_for_phi_arg_p (arg_false, alt_smaller))) | |
1214 | && (operand_equal_for_phi_arg_p (arg_true, larger) | |
1215 | || (alt_larger | |
1216 | && operand_equal_for_phi_arg_p (arg_true, alt_larger)))) | |
194899bf | 1217 | minmax = MAX_EXPR; |
1218 | else | |
1219 | return false; | |
1220 | } | |
1221 | else | |
1222 | { | |
1223 | /* Recognize the following case, assuming d <= u: | |
1224 | ||
1225 | if (a <= u) | |
1226 | b = MAX (a, d); | |
1227 | x = PHI <b, u> | |
1228 | ||
1229 | This is equivalent to | |
1230 | ||
1231 | b = MAX (a, d); | |
1232 | x = MIN (b, u); */ | |
1233 | ||
42acab1c | 1234 | gimple *assign = last_and_only_stmt (middle_bb); |
75a70cf9 | 1235 | tree lhs, op0, op1, bound; |
194899bf | 1236 | |
1237 | if (!assign | |
75a70cf9 | 1238 | || gimple_code (assign) != GIMPLE_ASSIGN) |
194899bf | 1239 | return false; |
1240 | ||
75a70cf9 | 1241 | lhs = gimple_assign_lhs (assign); |
1242 | ass_code = gimple_assign_rhs_code (assign); | |
194899bf | 1243 | if (ass_code != MAX_EXPR && ass_code != MIN_EXPR) |
1244 | return false; | |
75a70cf9 | 1245 | op0 = gimple_assign_rhs1 (assign); |
1246 | op1 = gimple_assign_rhs2 (assign); | |
194899bf | 1247 | |
1248 | if (true_edge->src == middle_bb) | |
1249 | { | |
1250 | /* We got here if the condition is true, i.e., SMALLER < LARGER. */ | |
1251 | if (!operand_equal_for_phi_arg_p (lhs, arg_true)) | |
1252 | return false; | |
1253 | ||
74201dc2 | 1254 | if (operand_equal_for_phi_arg_p (arg_false, larger) |
1255 | || (alt_larger | |
1256 | && operand_equal_for_phi_arg_p (arg_false, alt_larger))) | |
194899bf | 1257 | { |
1258 | /* Case | |
1259 | ||
1260 | if (smaller < larger) | |
1261 | { | |
1262 | r' = MAX_EXPR (smaller, bound) | |
1263 | } | |
1264 | r = PHI <r', larger> --> to be turned to MIN_EXPR. */ | |
1265 | if (ass_code != MAX_EXPR) | |
1266 | return false; | |
1267 | ||
1268 | minmax = MIN_EXPR; | |
74201dc2 | 1269 | if (operand_equal_for_phi_arg_p (op0, smaller) |
1270 | || (alt_smaller | |
1271 | && operand_equal_for_phi_arg_p (op0, alt_smaller))) | |
194899bf | 1272 | bound = op1; |
74201dc2 | 1273 | else if (operand_equal_for_phi_arg_p (op1, smaller) |
1274 | || (alt_smaller | |
1275 | && operand_equal_for_phi_arg_p (op1, alt_smaller))) | |
194899bf | 1276 | bound = op0; |
1277 | else | |
1278 | return false; | |
1279 | ||
1280 | /* We need BOUND <= LARGER. */ | |
49d00087 | 1281 | if (!integer_nonzerop (fold_build2 (LE_EXPR, boolean_type_node, |
1282 | bound, larger))) | |
194899bf | 1283 | return false; |
1284 | } | |
74201dc2 | 1285 | else if (operand_equal_for_phi_arg_p (arg_false, smaller) |
1286 | || (alt_smaller | |
1287 | && operand_equal_for_phi_arg_p (arg_false, alt_smaller))) | |
194899bf | 1288 | { |
1289 | /* Case | |
1290 | ||
1291 | if (smaller < larger) | |
1292 | { | |
1293 | r' = MIN_EXPR (larger, bound) | |
1294 | } | |
1295 | r = PHI <r', smaller> --> to be turned to MAX_EXPR. */ | |
1296 | if (ass_code != MIN_EXPR) | |
1297 | return false; | |
1298 | ||
1299 | minmax = MAX_EXPR; | |
74201dc2 | 1300 | if (operand_equal_for_phi_arg_p (op0, larger) |
1301 | || (alt_larger | |
1302 | && operand_equal_for_phi_arg_p (op0, alt_larger))) | |
194899bf | 1303 | bound = op1; |
74201dc2 | 1304 | else if (operand_equal_for_phi_arg_p (op1, larger) |
1305 | || (alt_larger | |
1306 | && operand_equal_for_phi_arg_p (op1, alt_larger))) | |
194899bf | 1307 | bound = op0; |
1308 | else | |
1309 | return false; | |
1310 | ||
1311 | /* We need BOUND >= SMALLER. */ | |
49d00087 | 1312 | if (!integer_nonzerop (fold_build2 (GE_EXPR, boolean_type_node, |
1313 | bound, smaller))) | |
194899bf | 1314 | return false; |
1315 | } | |
1316 | else | |
1317 | return false; | |
1318 | } | |
1319 | else | |
1320 | { | |
1321 | /* We got here if the condition is false, i.e., SMALLER > LARGER. */ | |
1322 | if (!operand_equal_for_phi_arg_p (lhs, arg_false)) | |
1323 | return false; | |
1324 | ||
74201dc2 | 1325 | if (operand_equal_for_phi_arg_p (arg_true, larger) |
1326 | || (alt_larger | |
1327 | && operand_equal_for_phi_arg_p (arg_true, alt_larger))) | |
194899bf | 1328 | { |
1329 | /* Case | |
1330 | ||
1331 | if (smaller > larger) | |
1332 | { | |
1333 | r' = MIN_EXPR (smaller, bound) | |
1334 | } | |
1335 | r = PHI <r', larger> --> to be turned to MAX_EXPR. */ | |
1336 | if (ass_code != MIN_EXPR) | |
1337 | return false; | |
1338 | ||
1339 | minmax = MAX_EXPR; | |
74201dc2 | 1340 | if (operand_equal_for_phi_arg_p (op0, smaller) |
1341 | || (alt_smaller | |
1342 | && operand_equal_for_phi_arg_p (op0, alt_smaller))) | |
194899bf | 1343 | bound = op1; |
74201dc2 | 1344 | else if (operand_equal_for_phi_arg_p (op1, smaller) |
1345 | || (alt_smaller | |
1346 | && operand_equal_for_phi_arg_p (op1, alt_smaller))) | |
194899bf | 1347 | bound = op0; |
1348 | else | |
1349 | return false; | |
1350 | ||
1351 | /* We need BOUND >= LARGER. */ | |
49d00087 | 1352 | if (!integer_nonzerop (fold_build2 (GE_EXPR, boolean_type_node, |
1353 | bound, larger))) | |
194899bf | 1354 | return false; |
1355 | } | |
74201dc2 | 1356 | else if (operand_equal_for_phi_arg_p (arg_true, smaller) |
1357 | || (alt_smaller | |
1358 | && operand_equal_for_phi_arg_p (arg_true, alt_smaller))) | |
194899bf | 1359 | { |
1360 | /* Case | |
1361 | ||
1362 | if (smaller > larger) | |
1363 | { | |
1364 | r' = MAX_EXPR (larger, bound) | |
1365 | } | |
1366 | r = PHI <r', smaller> --> to be turned to MIN_EXPR. */ | |
1367 | if (ass_code != MAX_EXPR) | |
1368 | return false; | |
1369 | ||
1370 | minmax = MIN_EXPR; | |
1371 | if (operand_equal_for_phi_arg_p (op0, larger)) | |
1372 | bound = op1; | |
1373 | else if (operand_equal_for_phi_arg_p (op1, larger)) | |
1374 | bound = op0; | |
1375 | else | |
1376 | return false; | |
1377 | ||
1378 | /* We need BOUND <= SMALLER. */ | |
49d00087 | 1379 | if (!integer_nonzerop (fold_build2 (LE_EXPR, boolean_type_node, |
1380 | bound, smaller))) | |
194899bf | 1381 | return false; |
1382 | } | |
1383 | else | |
1384 | return false; | |
1385 | } | |
1386 | ||
1387 | /* Move the statement from the middle block. */ | |
75a70cf9 | 1388 | gsi = gsi_last_bb (cond_bb); |
445a6ba5 | 1389 | gsi_from = gsi_last_nondebug_bb (middle_bb); |
75a70cf9 | 1390 | gsi_move_before (&gsi_from, &gsi); |
194899bf | 1391 | } |
1392 | ||
9b604bc1 | 1393 | /* Create an SSA var to hold the min/max result. If we're the only |
1394 | things setting the target PHI, then we can clone the PHI | |
1395 | variable. Otherwise we must create a new one. */ | |
1396 | result = PHI_RESULT (phi); | |
1397 | if (EDGE_COUNT (gimple_bb (phi)->preds) == 2) | |
1398 | result = duplicate_ssa_name (result, NULL); | |
1399 | else | |
1400 | result = make_ssa_name (TREE_TYPE (result)); | |
1401 | ||
194899bf | 1402 | /* Emit the statement to compute min/max. */ |
e9cf809e | 1403 | new_stmt = gimple_build_assign (result, minmax, arg0, arg1); |
75a70cf9 | 1404 | gsi = gsi_last_bb (cond_bb); |
1405 | gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT); | |
194899bf | 1406 | |
a4844041 | 1407 | replace_phi_edge_with_variable (cond_bb, e1, phi, result); |
8c1ab18f | 1408 | reset_flow_sensitive_info_in_bb (cond_bb); |
1409 | ||
194899bf | 1410 | return true; |
1411 | } | |
1412 | ||
70512b93 | 1413 | /* The function absolute_replacement does the main work of doing the absolute |
1414 | replacement. Return true if the replacement is done. Otherwise return | |
1415 | false. | |
1416 | bb is the basic block where the replacement is going to be done on. arg0 | |
f7f07c95 | 1417 | is argument 0 from the phi. Likewise for arg1. */ |
33784d89 | 1418 | |
70512b93 | 1419 | static bool |
33784d89 | 1420 | abs_replacement (basic_block cond_bb, basic_block middle_bb, |
a4844041 | 1421 | edge e0 ATTRIBUTE_UNUSED, edge e1, |
42acab1c | 1422 | gimple *phi, tree arg0, tree arg1) |
70512b93 | 1423 | { |
1424 | tree result; | |
1a91d914 | 1425 | gassign *new_stmt; |
42acab1c | 1426 | gimple *cond; |
75a70cf9 | 1427 | gimple_stmt_iterator gsi; |
70512b93 | 1428 | edge true_edge, false_edge; |
42acab1c | 1429 | gimple *assign; |
70512b93 | 1430 | edge e; |
194899bf | 1431 | tree rhs, lhs; |
70512b93 | 1432 | bool negate; |
1433 | enum tree_code cond_code; | |
1434 | ||
1435 | /* If the type says honor signed zeros we cannot do this | |
dac49aa5 | 1436 | optimization. */ |
fe994837 | 1437 | if (HONOR_SIGNED_ZEROS (arg1)) |
70512b93 | 1438 | return false; |
1439 | ||
70512b93 | 1440 | /* OTHER_BLOCK must have only one executable statement which must have the |
1441 | form arg0 = -arg1 or arg1 = -arg0. */ | |
70512b93 | 1442 | |
194899bf | 1443 | assign = last_and_only_stmt (middle_bb); |
70512b93 | 1444 | /* If we did not find the proper negation assignment, then we can not |
1445 | optimize. */ | |
1446 | if (assign == NULL) | |
1447 | return false; | |
48e1416a | 1448 | |
194899bf | 1449 | /* If we got here, then we have found the only executable statement |
1450 | in OTHER_BLOCK. If it is anything other than arg = -arg1 or | |
1451 | arg1 = -arg0, then we can not optimize. */ | |
75a70cf9 | 1452 | if (gimple_code (assign) != GIMPLE_ASSIGN) |
194899bf | 1453 | return false; |
1454 | ||
75a70cf9 | 1455 | lhs = gimple_assign_lhs (assign); |
194899bf | 1456 | |
75a70cf9 | 1457 | if (gimple_assign_rhs_code (assign) != NEGATE_EXPR) |
194899bf | 1458 | return false; |
1459 | ||
75a70cf9 | 1460 | rhs = gimple_assign_rhs1 (assign); |
48e1416a | 1461 | |
194899bf | 1462 | /* The assignment has to be arg0 = -arg1 or arg1 = -arg0. */ |
1463 | if (!(lhs == arg0 && rhs == arg1) | |
1464 | && !(lhs == arg1 && rhs == arg0)) | |
1465 | return false; | |
70512b93 | 1466 | |
75a70cf9 | 1467 | cond = last_stmt (cond_bb); |
70512b93 | 1468 | result = PHI_RESULT (phi); |
1469 | ||
1470 | /* Only relationals comparing arg[01] against zero are interesting. */ | |
75a70cf9 | 1471 | cond_code = gimple_cond_code (cond); |
70512b93 | 1472 | if (cond_code != GT_EXPR && cond_code != GE_EXPR |
1473 | && cond_code != LT_EXPR && cond_code != LE_EXPR) | |
1474 | return false; | |
1475 | ||
dac49aa5 | 1476 | /* Make sure the conditional is arg[01] OP y. */ |
75a70cf9 | 1477 | if (gimple_cond_lhs (cond) != rhs) |
70512b93 | 1478 | return false; |
1479 | ||
75a70cf9 | 1480 | if (FLOAT_TYPE_P (TREE_TYPE (gimple_cond_rhs (cond))) |
1481 | ? real_zerop (gimple_cond_rhs (cond)) | |
1482 | : integer_zerop (gimple_cond_rhs (cond))) | |
70512b93 | 1483 | ; |
1484 | else | |
1485 | return false; | |
1486 | ||
1487 | /* We need to know which is the true edge and which is the false | |
1488 | edge so that we know if have abs or negative abs. */ | |
33784d89 | 1489 | extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge); |
70512b93 | 1490 | |
1491 | /* For GT_EXPR/GE_EXPR, if the true edge goes to OTHER_BLOCK, then we | |
1492 | will need to negate the result. Similarly for LT_EXPR/LE_EXPR if | |
1493 | the false edge goes to OTHER_BLOCK. */ | |
1494 | if (cond_code == GT_EXPR || cond_code == GE_EXPR) | |
1495 | e = true_edge; | |
1496 | else | |
1497 | e = false_edge; | |
20e5647c | 1498 | |
33784d89 | 1499 | if (e->dest == middle_bb) |
70512b93 | 1500 | negate = true; |
1501 | else | |
1502 | negate = false; | |
20e5647c | 1503 | |
57b2dea1 | 1504 | /* If the code negates only iff positive then make sure to not |
1505 | introduce undefined behavior when negating or computing the absolute. | |
1506 | ??? We could use range info if present to check for arg1 == INT_MIN. */ | |
1507 | if (negate | |
1508 | && (ANY_INTEGRAL_TYPE_P (TREE_TYPE (arg1)) | |
1509 | && ! TYPE_OVERFLOW_WRAPS (TREE_TYPE (arg1)))) | |
1510 | return false; | |
1511 | ||
33784d89 | 1512 | result = duplicate_ssa_name (result, NULL); |
20e5647c | 1513 | |
70512b93 | 1514 | if (negate) |
f9e245b2 | 1515 | lhs = make_ssa_name (TREE_TYPE (result)); |
70512b93 | 1516 | else |
1517 | lhs = result; | |
1518 | ||
dac49aa5 | 1519 | /* Build the modify expression with abs expression. */ |
e9cf809e | 1520 | new_stmt = gimple_build_assign (lhs, ABS_EXPR, rhs); |
70512b93 | 1521 | |
75a70cf9 | 1522 | gsi = gsi_last_bb (cond_bb); |
1523 | gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT); | |
70512b93 | 1524 | |
1525 | if (negate) | |
1526 | { | |
75a70cf9 | 1527 | /* Get the right GSI. We want to insert after the recently |
70512b93 | 1528 | added ABS_EXPR statement (which we know is the first statement |
1529 | in the block. */ | |
e9cf809e | 1530 | new_stmt = gimple_build_assign (result, NEGATE_EXPR, lhs); |
70512b93 | 1531 | |
75a70cf9 | 1532 | gsi_insert_after (&gsi, new_stmt, GSI_NEW_STMT); |
70512b93 | 1533 | } |
20e5647c | 1534 | |
a4844041 | 1535 | replace_phi_edge_with_variable (cond_bb, e1, phi, result); |
8c1ab18f | 1536 | reset_flow_sensitive_info_in_bb (cond_bb); |
70512b93 | 1537 | |
1538 | /* Note that we optimized this PHI. */ | |
1539 | return true; | |
1540 | } | |
1541 | ||
e6d0e152 | 1542 | /* Auxiliary functions to determine the set of memory accesses which |
1543 | can't trap because they are preceded by accesses to the same memory | |
182cf5a9 | 1544 | portion. We do that for MEM_REFs, so we only need to track |
e6d0e152 | 1545 | the SSA_NAME of the pointer indirectly referenced. The algorithm |
1546 | simply is a walk over all instructions in dominator order. When | |
182cf5a9 | 1547 | we see an MEM_REF we determine if we've already seen a same |
e6d0e152 | 1548 | ref anywhere up to the root of the dominator tree. If we do the |
af4f74fa | 1549 | current access can't trap. If we don't see any dominating access |
e6d0e152 | 1550 | the current access might trap, but might also make later accesses |
af4f74fa | 1551 | non-trapping, so we remember it. We need to be careful with loads |
1552 | or stores, for instance a load might not trap, while a store would, | |
1553 | so if we see a dominating read access this doesn't mean that a later | |
1554 | write access would not trap. Hence we also need to differentiate the | |
1555 | type of access(es) seen. | |
1556 | ||
1557 | ??? We currently are very conservative and assume that a load might | |
1558 | trap even if a store doesn't (write-only memory). This probably is | |
1559 | overly conservative. */ | |
e6d0e152 | 1560 | |
182cf5a9 | 1561 | /* A hash-table of SSA_NAMEs, and in which basic block an MEM_REF |
e6d0e152 | 1562 | through it was seen, which would constitute a no-trap region for |
1563 | same accesses. */ | |
1564 | struct name_to_bb | |
1565 | { | |
963aee26 | 1566 | unsigned int ssa_name_ver; |
42540642 | 1567 | unsigned int phase; |
963aee26 | 1568 | bool store; |
1569 | HOST_WIDE_INT offset, size; | |
e6d0e152 | 1570 | basic_block bb; |
1571 | }; | |
1572 | ||
d9dd21a8 | 1573 | /* Hashtable helpers. */ |
1574 | ||
298e7f9a | 1575 | struct ssa_names_hasher : free_ptr_hash <name_to_bb> |
d9dd21a8 | 1576 | { |
9969c043 | 1577 | static inline hashval_t hash (const name_to_bb *); |
1578 | static inline bool equal (const name_to_bb *, const name_to_bb *); | |
d9dd21a8 | 1579 | }; |
e6d0e152 | 1580 | |
42540642 | 1581 | /* Used for quick clearing of the hash-table when we see calls. |
1582 | Hash entries with phase < nt_call_phase are invalid. */ | |
1583 | static unsigned int nt_call_phase; | |
1584 | ||
963aee26 | 1585 | /* The hash function. */ |
d9dd21a8 | 1586 | |
1587 | inline hashval_t | |
9969c043 | 1588 | ssa_names_hasher::hash (const name_to_bb *n) |
e6d0e152 | 1589 | { |
963aee26 | 1590 | return n->ssa_name_ver ^ (((hashval_t) n->store) << 31) |
1591 | ^ (n->offset << 6) ^ (n->size << 3); | |
e6d0e152 | 1592 | } |
1593 | ||
963aee26 | 1594 | /* The equality function of *P1 and *P2. */ |
e6d0e152 | 1595 | |
d9dd21a8 | 1596 | inline bool |
9969c043 | 1597 | ssa_names_hasher::equal (const name_to_bb *n1, const name_to_bb *n2) |
d9dd21a8 | 1598 | { |
963aee26 | 1599 | return n1->ssa_name_ver == n2->ssa_name_ver |
1600 | && n1->store == n2->store | |
1601 | && n1->offset == n2->offset | |
1602 | && n1->size == n2->size; | |
e6d0e152 | 1603 | } |
1604 | ||
c1f445d2 | 1605 | class nontrapping_dom_walker : public dom_walker |
1606 | { | |
1607 | public: | |
431205b7 | 1608 | nontrapping_dom_walker (cdi_direction direction, hash_set<tree> *ps) |
c1f445d2 | 1609 | : dom_walker (direction), m_nontrapping (ps), m_seen_ssa_names (128) {} |
1610 | ||
96752458 | 1611 | virtual edge before_dom_children (basic_block); |
c1f445d2 | 1612 | virtual void after_dom_children (basic_block); |
1613 | ||
1614 | private: | |
1615 | ||
1616 | /* We see the expression EXP in basic block BB. If it's an interesting | |
1617 | expression (an MEM_REF through an SSA_NAME) possibly insert the | |
1618 | expression into the set NONTRAP or the hash table of seen expressions. | |
1619 | STORE is true if this expression is on the LHS, otherwise it's on | |
1620 | the RHS. */ | |
1621 | void add_or_mark_expr (basic_block, tree, bool); | |
1622 | ||
431205b7 | 1623 | hash_set<tree> *m_nontrapping; |
c1f445d2 | 1624 | |
1625 | /* The hash table for remembering what we've seen. */ | |
1626 | hash_table<ssa_names_hasher> m_seen_ssa_names; | |
1627 | }; | |
1628 | ||
1629 | /* Called by walk_dominator_tree, when entering the block BB. */ | |
96752458 | 1630 | edge |
c1f445d2 | 1631 | nontrapping_dom_walker::before_dom_children (basic_block bb) |
1632 | { | |
1633 | edge e; | |
1634 | edge_iterator ei; | |
1635 | gimple_stmt_iterator gsi; | |
1636 | ||
1637 | /* If we haven't seen all our predecessors, clear the hash-table. */ | |
1638 | FOR_EACH_EDGE (e, ei, bb->preds) | |
1639 | if ((((size_t)e->src->aux) & 2) == 0) | |
1640 | { | |
1641 | nt_call_phase++; | |
1642 | break; | |
1643 | } | |
1644 | ||
1645 | /* Mark this BB as being on the path to dominator root and as visited. */ | |
1646 | bb->aux = (void*)(1 | 2); | |
1647 | ||
1648 | /* And walk the statements in order. */ | |
1649 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
1650 | { | |
42acab1c | 1651 | gimple *stmt = gsi_stmt (gsi); |
c1f445d2 | 1652 | |
05a63389 | 1653 | if ((gimple_code (stmt) == GIMPLE_ASM && gimple_vdef (stmt)) |
1654 | || (is_gimple_call (stmt) | |
1655 | && (!nonfreeing_call_p (stmt) || !nonbarrier_call_p (stmt)))) | |
c1f445d2 | 1656 | nt_call_phase++; |
1657 | else if (gimple_assign_single_p (stmt) && !gimple_has_volatile_ops (stmt)) | |
1658 | { | |
1659 | add_or_mark_expr (bb, gimple_assign_lhs (stmt), true); | |
1660 | add_or_mark_expr (bb, gimple_assign_rhs1 (stmt), false); | |
1661 | } | |
1662 | } | |
96752458 | 1663 | return NULL; |
c1f445d2 | 1664 | } |
1665 | ||
1666 | /* Called by walk_dominator_tree, when basic block BB is exited. */ | |
1667 | void | |
1668 | nontrapping_dom_walker::after_dom_children (basic_block bb) | |
1669 | { | |
1670 | /* This BB isn't on the path to dominator root anymore. */ | |
1671 | bb->aux = (void*)2; | |
1672 | } | |
d9dd21a8 | 1673 | |
f0b5f617 | 1674 | /* We see the expression EXP in basic block BB. If it's an interesting |
182cf5a9 | 1675 | expression (an MEM_REF through an SSA_NAME) possibly insert the |
af4f74fa | 1676 | expression into the set NONTRAP or the hash table of seen expressions. |
1677 | STORE is true if this expression is on the LHS, otherwise it's on | |
1678 | the RHS. */ | |
c1f445d2 | 1679 | void |
1680 | nontrapping_dom_walker::add_or_mark_expr (basic_block bb, tree exp, bool store) | |
e6d0e152 | 1681 | { |
963aee26 | 1682 | HOST_WIDE_INT size; |
1683 | ||
182cf5a9 | 1684 | if (TREE_CODE (exp) == MEM_REF |
963aee26 | 1685 | && TREE_CODE (TREE_OPERAND (exp, 0)) == SSA_NAME |
e913b5cd | 1686 | && tree_fits_shwi_p (TREE_OPERAND (exp, 1)) |
963aee26 | 1687 | && (size = int_size_in_bytes (TREE_TYPE (exp))) > 0) |
e6d0e152 | 1688 | { |
1689 | tree name = TREE_OPERAND (exp, 0); | |
1690 | struct name_to_bb map; | |
d9dd21a8 | 1691 | name_to_bb **slot; |
af4f74fa | 1692 | struct name_to_bb *n2bb; |
e6d0e152 | 1693 | basic_block found_bb = 0; |
1694 | ||
182cf5a9 | 1695 | /* Try to find the last seen MEM_REF through the same |
e6d0e152 | 1696 | SSA_NAME, which can trap. */ |
963aee26 | 1697 | map.ssa_name_ver = SSA_NAME_VERSION (name); |
42540642 | 1698 | map.phase = 0; |
e6d0e152 | 1699 | map.bb = 0; |
af4f74fa | 1700 | map.store = store; |
e913b5cd | 1701 | map.offset = tree_to_shwi (TREE_OPERAND (exp, 1)); |
963aee26 | 1702 | map.size = size; |
1703 | ||
c1f445d2 | 1704 | slot = m_seen_ssa_names.find_slot (&map, INSERT); |
d9dd21a8 | 1705 | n2bb = *slot; |
42540642 | 1706 | if (n2bb && n2bb->phase >= nt_call_phase) |
af4f74fa | 1707 | found_bb = n2bb->bb; |
e6d0e152 | 1708 | |
182cf5a9 | 1709 | /* If we've found a trapping MEM_REF, _and_ it dominates EXP |
e6d0e152 | 1710 | (it's in a basic block on the path from us to the dominator root) |
1711 | then we can't trap. */ | |
42540642 | 1712 | if (found_bb && (((size_t)found_bb->aux) & 1) == 1) |
e6d0e152 | 1713 | { |
431205b7 | 1714 | m_nontrapping->add (exp); |
e6d0e152 | 1715 | } |
1716 | else | |
1717 | { | |
1718 | /* EXP might trap, so insert it into the hash table. */ | |
af4f74fa | 1719 | if (n2bb) |
e6d0e152 | 1720 | { |
42540642 | 1721 | n2bb->phase = nt_call_phase; |
af4f74fa | 1722 | n2bb->bb = bb; |
e6d0e152 | 1723 | } |
1724 | else | |
1725 | { | |
af4f74fa | 1726 | n2bb = XNEW (struct name_to_bb); |
963aee26 | 1727 | n2bb->ssa_name_ver = SSA_NAME_VERSION (name); |
42540642 | 1728 | n2bb->phase = nt_call_phase; |
af4f74fa | 1729 | n2bb->bb = bb; |
1730 | n2bb->store = store; | |
963aee26 | 1731 | n2bb->offset = map.offset; |
1732 | n2bb->size = size; | |
af4f74fa | 1733 | *slot = n2bb; |
e6d0e152 | 1734 | } |
1735 | } | |
1736 | } | |
1737 | } | |
1738 | ||
e6d0e152 | 1739 | /* This is the entry point of gathering non trapping memory accesses. |
1740 | It will do a dominator walk over the whole function, and it will | |
1741 | make use of the bb->aux pointers. It returns a set of trees | |
182cf5a9 | 1742 | (the MEM_REFs itself) which can't trap. */ |
431205b7 | 1743 | static hash_set<tree> * |
e6d0e152 | 1744 | get_non_trapping (void) |
1745 | { | |
42540642 | 1746 | nt_call_phase = 0; |
431205b7 | 1747 | hash_set<tree> *nontrap = new hash_set<tree>; |
e6d0e152 | 1748 | /* We're going to do a dominator walk, so ensure that we have |
1749 | dominance information. */ | |
1750 | calculate_dominance_info (CDI_DOMINATORS); | |
1751 | ||
54c91640 | 1752 | nontrapping_dom_walker (CDI_DOMINATORS, nontrap) |
1753 | .walk (cfun->cfg->x_entry_block_ptr); | |
1754 | ||
42540642 | 1755 | clear_aux_for_blocks (); |
e6d0e152 | 1756 | return nontrap; |
1757 | } | |
1758 | ||
1759 | /* Do the main work of conditional store replacement. We already know | |
1760 | that the recognized pattern looks like so: | |
1761 | ||
1762 | split: | |
1763 | if (cond) goto MIDDLE_BB; else goto JOIN_BB (edge E1) | |
1764 | MIDDLE_BB: | |
1765 | something | |
1766 | fallthrough (edge E0) | |
1767 | JOIN_BB: | |
1768 | some more | |
1769 | ||
1770 | We check that MIDDLE_BB contains only one store, that that store | |
1771 | doesn't trap (not via NOTRAP, but via checking if an access to the same | |
1772 | memory location dominates us) and that the store has a "simple" RHS. */ | |
1773 | ||
1774 | static bool | |
1775 | cond_store_replacement (basic_block middle_bb, basic_block join_bb, | |
431205b7 | 1776 | edge e0, edge e1, hash_set<tree> *nontrap) |
e6d0e152 | 1777 | { |
42acab1c | 1778 | gimple *assign = last_and_only_stmt (middle_bb); |
03d37e4e | 1779 | tree lhs, rhs, name, name2; |
1a91d914 | 1780 | gphi *newphi; |
1781 | gassign *new_stmt; | |
75a70cf9 | 1782 | gimple_stmt_iterator gsi; |
efbcb6de | 1783 | source_location locus; |
e6d0e152 | 1784 | |
1785 | /* Check if middle_bb contains of only one store. */ | |
1786 | if (!assign | |
6cc085b6 | 1787 | || !gimple_assign_single_p (assign) |
1788 | || gimple_has_volatile_ops (assign)) | |
e6d0e152 | 1789 | return false; |
1790 | ||
efbcb6de | 1791 | locus = gimple_location (assign); |
75a70cf9 | 1792 | lhs = gimple_assign_lhs (assign); |
1793 | rhs = gimple_assign_rhs1 (assign); | |
182cf5a9 | 1794 | if (TREE_CODE (lhs) != MEM_REF |
91cf53d5 | 1795 | || TREE_CODE (TREE_OPERAND (lhs, 0)) != SSA_NAME |
3211fa0a | 1796 | || !is_gimple_reg_type (TREE_TYPE (lhs))) |
e6d0e152 | 1797 | return false; |
91cf53d5 | 1798 | |
e6d0e152 | 1799 | /* Prove that we can move the store down. We could also check |
1800 | TREE_THIS_NOTRAP here, but in that case we also could move stores, | |
1801 | whose value is not available readily, which we want to avoid. */ | |
431205b7 | 1802 | if (!nontrap->contains (lhs)) |
e6d0e152 | 1803 | return false; |
1804 | ||
1805 | /* Now we've checked the constraints, so do the transformation: | |
1806 | 1) Remove the single store. */ | |
75a70cf9 | 1807 | gsi = gsi_for_stmt (assign); |
3211fa0a | 1808 | unlink_stmt_vdef (assign); |
75a70cf9 | 1809 | gsi_remove (&gsi, true); |
91cf53d5 | 1810 | release_defs (assign); |
e6d0e152 | 1811 | |
03d37e4e | 1812 | /* 2) Insert a load from the memory of the store to the temporary |
e6d0e152 | 1813 | on the edge which did not contain the store. */ |
1814 | lhs = unshare_expr (lhs); | |
03d37e4e | 1815 | name = make_temp_ssa_name (TREE_TYPE (lhs), NULL, "cstore"); |
1816 | new_stmt = gimple_build_assign (name, lhs); | |
efbcb6de | 1817 | gimple_set_location (new_stmt, locus); |
75a70cf9 | 1818 | gsi_insert_on_edge (e1, new_stmt); |
e6d0e152 | 1819 | |
03d37e4e | 1820 | /* 3) Create a PHI node at the join block, with one argument |
e6d0e152 | 1821 | holding the old RHS, and the other holding the temporary |
1822 | where we stored the old memory contents. */ | |
03d37e4e | 1823 | name2 = make_temp_ssa_name (TREE_TYPE (lhs), NULL, "cstore"); |
1824 | newphi = create_phi_node (name2, join_bb); | |
60d535d2 | 1825 | add_phi_arg (newphi, rhs, e0, locus); |
1826 | add_phi_arg (newphi, name, e1, locus); | |
e6d0e152 | 1827 | |
1828 | lhs = unshare_expr (lhs); | |
75a70cf9 | 1829 | new_stmt = gimple_build_assign (lhs, PHI_RESULT (newphi)); |
e6d0e152 | 1830 | |
03d37e4e | 1831 | /* 4) Insert that PHI node. */ |
75a70cf9 | 1832 | gsi = gsi_after_labels (join_bb); |
1833 | if (gsi_end_p (gsi)) | |
e6d0e152 | 1834 | { |
75a70cf9 | 1835 | gsi = gsi_last_bb (join_bb); |
1836 | gsi_insert_after (&gsi, new_stmt, GSI_NEW_STMT); | |
e6d0e152 | 1837 | } |
1838 | else | |
75a70cf9 | 1839 | gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT); |
e6d0e152 | 1840 | |
1841 | return true; | |
1842 | } | |
4ee9c684 | 1843 | |
ec611e12 | 1844 | /* Do the main work of conditional store replacement. */ |
91cf53d5 | 1845 | |
1846 | static bool | |
ec611e12 | 1847 | cond_if_else_store_replacement_1 (basic_block then_bb, basic_block else_bb, |
42acab1c | 1848 | basic_block join_bb, gimple *then_assign, |
1849 | gimple *else_assign) | |
91cf53d5 | 1850 | { |
03d37e4e | 1851 | tree lhs_base, lhs, then_rhs, else_rhs, name; |
91cf53d5 | 1852 | source_location then_locus, else_locus; |
1853 | gimple_stmt_iterator gsi; | |
1a91d914 | 1854 | gphi *newphi; |
1855 | gassign *new_stmt; | |
91cf53d5 | 1856 | |
91cf53d5 | 1857 | if (then_assign == NULL |
1858 | || !gimple_assign_single_p (then_assign) | |
3c25489e | 1859 | || gimple_clobber_p (then_assign) |
6cc085b6 | 1860 | || gimple_has_volatile_ops (then_assign) |
91cf53d5 | 1861 | || else_assign == NULL |
3c25489e | 1862 | || !gimple_assign_single_p (else_assign) |
6cc085b6 | 1863 | || gimple_clobber_p (else_assign) |
1864 | || gimple_has_volatile_ops (else_assign)) | |
91cf53d5 | 1865 | return false; |
1866 | ||
1867 | lhs = gimple_assign_lhs (then_assign); | |
1868 | if (!is_gimple_reg_type (TREE_TYPE (lhs)) | |
1869 | || !operand_equal_p (lhs, gimple_assign_lhs (else_assign), 0)) | |
1870 | return false; | |
1871 | ||
1872 | lhs_base = get_base_address (lhs); | |
1873 | if (lhs_base == NULL_TREE | |
1874 | || (!DECL_P (lhs_base) && TREE_CODE (lhs_base) != MEM_REF)) | |
1875 | return false; | |
1876 | ||
1877 | then_rhs = gimple_assign_rhs1 (then_assign); | |
1878 | else_rhs = gimple_assign_rhs1 (else_assign); | |
1879 | then_locus = gimple_location (then_assign); | |
1880 | else_locus = gimple_location (else_assign); | |
1881 | ||
1882 | /* Now we've checked the constraints, so do the transformation: | |
1883 | 1) Remove the stores. */ | |
1884 | gsi = gsi_for_stmt (then_assign); | |
1885 | unlink_stmt_vdef (then_assign); | |
1886 | gsi_remove (&gsi, true); | |
1887 | release_defs (then_assign); | |
1888 | ||
1889 | gsi = gsi_for_stmt (else_assign); | |
1890 | unlink_stmt_vdef (else_assign); | |
1891 | gsi_remove (&gsi, true); | |
1892 | release_defs (else_assign); | |
1893 | ||
03d37e4e | 1894 | /* 2) Create a PHI node at the join block, with one argument |
91cf53d5 | 1895 | holding the old RHS, and the other holding the temporary |
1896 | where we stored the old memory contents. */ | |
03d37e4e | 1897 | name = make_temp_ssa_name (TREE_TYPE (lhs), NULL, "cstore"); |
1898 | newphi = create_phi_node (name, join_bb); | |
60d535d2 | 1899 | add_phi_arg (newphi, then_rhs, EDGE_SUCC (then_bb, 0), then_locus); |
1900 | add_phi_arg (newphi, else_rhs, EDGE_SUCC (else_bb, 0), else_locus); | |
91cf53d5 | 1901 | |
1902 | new_stmt = gimple_build_assign (lhs, PHI_RESULT (newphi)); | |
1903 | ||
03d37e4e | 1904 | /* 3) Insert that PHI node. */ |
91cf53d5 | 1905 | gsi = gsi_after_labels (join_bb); |
1906 | if (gsi_end_p (gsi)) | |
1907 | { | |
1908 | gsi = gsi_last_bb (join_bb); | |
1909 | gsi_insert_after (&gsi, new_stmt, GSI_NEW_STMT); | |
1910 | } | |
1911 | else | |
1912 | gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT); | |
1913 | ||
1914 | return true; | |
1915 | } | |
1916 | ||
ec611e12 | 1917 | /* Conditional store replacement. We already know |
1918 | that the recognized pattern looks like so: | |
1919 | ||
1920 | split: | |
1921 | if (cond) goto THEN_BB; else goto ELSE_BB (edge E1) | |
1922 | THEN_BB: | |
1923 | ... | |
1924 | X = Y; | |
1925 | ... | |
1926 | goto JOIN_BB; | |
1927 | ELSE_BB: | |
1928 | ... | |
1929 | X = Z; | |
1930 | ... | |
1931 | fallthrough (edge E0) | |
1932 | JOIN_BB: | |
1933 | some more | |
1934 | ||
1935 | We check that it is safe to sink the store to JOIN_BB by verifying that | |
1936 | there are no read-after-write or write-after-write dependencies in | |
1937 | THEN_BB and ELSE_BB. */ | |
1938 | ||
1939 | static bool | |
1940 | cond_if_else_store_replacement (basic_block then_bb, basic_block else_bb, | |
1941 | basic_block join_bb) | |
1942 | { | |
42acab1c | 1943 | gimple *then_assign = last_and_only_stmt (then_bb); |
1944 | gimple *else_assign = last_and_only_stmt (else_bb); | |
f1f41a6c | 1945 | vec<data_reference_p> then_datarefs, else_datarefs; |
1946 | vec<ddr_p> then_ddrs, else_ddrs; | |
42acab1c | 1947 | gimple *then_store, *else_store; |
ec611e12 | 1948 | bool found, ok = false, res; |
1949 | struct data_dependence_relation *ddr; | |
1950 | data_reference_p then_dr, else_dr; | |
1951 | int i, j; | |
1952 | tree then_lhs, else_lhs; | |
ec611e12 | 1953 | basic_block blocks[3]; |
1954 | ||
1955 | if (MAX_STORES_TO_SINK == 0) | |
1956 | return false; | |
1957 | ||
1958 | /* Handle the case with single statement in THEN_BB and ELSE_BB. */ | |
1959 | if (then_assign && else_assign) | |
1960 | return cond_if_else_store_replacement_1 (then_bb, else_bb, join_bb, | |
1961 | then_assign, else_assign); | |
1962 | ||
1963 | /* Find data references. */ | |
f1f41a6c | 1964 | then_datarefs.create (1); |
1965 | else_datarefs.create (1); | |
ec611e12 | 1966 | if ((find_data_references_in_bb (NULL, then_bb, &then_datarefs) |
1967 | == chrec_dont_know) | |
f1f41a6c | 1968 | || !then_datarefs.length () |
ec611e12 | 1969 | || (find_data_references_in_bb (NULL, else_bb, &else_datarefs) |
c71d3c24 | 1970 | == chrec_dont_know) |
f1f41a6c | 1971 | || !else_datarefs.length ()) |
ec611e12 | 1972 | { |
1973 | free_data_refs (then_datarefs); | |
1974 | free_data_refs (else_datarefs); | |
1975 | return false; | |
1976 | } | |
1977 | ||
1978 | /* Find pairs of stores with equal LHS. */ | |
42acab1c | 1979 | auto_vec<gimple *, 1> then_stores, else_stores; |
f1f41a6c | 1980 | FOR_EACH_VEC_ELT (then_datarefs, i, then_dr) |
ec611e12 | 1981 | { |
1982 | if (DR_IS_READ (then_dr)) | |
1983 | continue; | |
1984 | ||
1985 | then_store = DR_STMT (then_dr); | |
728dcc71 | 1986 | then_lhs = gimple_get_lhs (then_store); |
c71d3c24 | 1987 | if (then_lhs == NULL_TREE) |
1988 | continue; | |
ec611e12 | 1989 | found = false; |
1990 | ||
f1f41a6c | 1991 | FOR_EACH_VEC_ELT (else_datarefs, j, else_dr) |
ec611e12 | 1992 | { |
1993 | if (DR_IS_READ (else_dr)) | |
1994 | continue; | |
1995 | ||
1996 | else_store = DR_STMT (else_dr); | |
728dcc71 | 1997 | else_lhs = gimple_get_lhs (else_store); |
c71d3c24 | 1998 | if (else_lhs == NULL_TREE) |
1999 | continue; | |
ec611e12 | 2000 | |
2001 | if (operand_equal_p (then_lhs, else_lhs, 0)) | |
2002 | { | |
2003 | found = true; | |
2004 | break; | |
2005 | } | |
2006 | } | |
2007 | ||
2008 | if (!found) | |
2009 | continue; | |
2010 | ||
f1f41a6c | 2011 | then_stores.safe_push (then_store); |
2012 | else_stores.safe_push (else_store); | |
ec611e12 | 2013 | } |
2014 | ||
2015 | /* No pairs of stores found. */ | |
f1f41a6c | 2016 | if (!then_stores.length () |
2017 | || then_stores.length () > (unsigned) MAX_STORES_TO_SINK) | |
ec611e12 | 2018 | { |
2019 | free_data_refs (then_datarefs); | |
2020 | free_data_refs (else_datarefs); | |
ec611e12 | 2021 | return false; |
2022 | } | |
2023 | ||
2024 | /* Compute and check data dependencies in both basic blocks. */ | |
f1f41a6c | 2025 | then_ddrs.create (1); |
2026 | else_ddrs.create (1); | |
2027 | if (!compute_all_dependences (then_datarefs, &then_ddrs, | |
1e094109 | 2028 | vNULL, false) |
f1f41a6c | 2029 | || !compute_all_dependences (else_datarefs, &else_ddrs, |
1e094109 | 2030 | vNULL, false)) |
8b3fb720 | 2031 | { |
2032 | free_dependence_relations (then_ddrs); | |
2033 | free_dependence_relations (else_ddrs); | |
2034 | free_data_refs (then_datarefs); | |
2035 | free_data_refs (else_datarefs); | |
8b3fb720 | 2036 | return false; |
2037 | } | |
ec611e12 | 2038 | blocks[0] = then_bb; |
2039 | blocks[1] = else_bb; | |
2040 | blocks[2] = join_bb; | |
2041 | renumber_gimple_stmt_uids_in_blocks (blocks, 3); | |
2042 | ||
2043 | /* Check that there are no read-after-write or write-after-write dependencies | |
2044 | in THEN_BB. */ | |
f1f41a6c | 2045 | FOR_EACH_VEC_ELT (then_ddrs, i, ddr) |
ec611e12 | 2046 | { |
2047 | struct data_reference *dra = DDR_A (ddr); | |
2048 | struct data_reference *drb = DDR_B (ddr); | |
2049 | ||
2050 | if (DDR_ARE_DEPENDENT (ddr) != chrec_known | |
2051 | && ((DR_IS_READ (dra) && DR_IS_WRITE (drb) | |
2052 | && gimple_uid (DR_STMT (dra)) > gimple_uid (DR_STMT (drb))) | |
2053 | || (DR_IS_READ (drb) && DR_IS_WRITE (dra) | |
2054 | && gimple_uid (DR_STMT (drb)) > gimple_uid (DR_STMT (dra))) | |
2055 | || (DR_IS_WRITE (dra) && DR_IS_WRITE (drb)))) | |
2056 | { | |
2057 | free_dependence_relations (then_ddrs); | |
2058 | free_dependence_relations (else_ddrs); | |
2473bfb7 | 2059 | free_data_refs (then_datarefs); |
2060 | free_data_refs (else_datarefs); | |
ec611e12 | 2061 | return false; |
2062 | } | |
2063 | } | |
2064 | ||
2065 | /* Check that there are no read-after-write or write-after-write dependencies | |
2066 | in ELSE_BB. */ | |
f1f41a6c | 2067 | FOR_EACH_VEC_ELT (else_ddrs, i, ddr) |
ec611e12 | 2068 | { |
2069 | struct data_reference *dra = DDR_A (ddr); | |
2070 | struct data_reference *drb = DDR_B (ddr); | |
2071 | ||
2072 | if (DDR_ARE_DEPENDENT (ddr) != chrec_known | |
2073 | && ((DR_IS_READ (dra) && DR_IS_WRITE (drb) | |
2074 | && gimple_uid (DR_STMT (dra)) > gimple_uid (DR_STMT (drb))) | |
2075 | || (DR_IS_READ (drb) && DR_IS_WRITE (dra) | |
2076 | && gimple_uid (DR_STMT (drb)) > gimple_uid (DR_STMT (dra))) | |
2077 | || (DR_IS_WRITE (dra) && DR_IS_WRITE (drb)))) | |
2078 | { | |
2079 | free_dependence_relations (then_ddrs); | |
2080 | free_dependence_relations (else_ddrs); | |
2473bfb7 | 2081 | free_data_refs (then_datarefs); |
2082 | free_data_refs (else_datarefs); | |
ec611e12 | 2083 | return false; |
2084 | } | |
2085 | } | |
2086 | ||
2087 | /* Sink stores with same LHS. */ | |
f1f41a6c | 2088 | FOR_EACH_VEC_ELT (then_stores, i, then_store) |
ec611e12 | 2089 | { |
f1f41a6c | 2090 | else_store = else_stores[i]; |
ec611e12 | 2091 | res = cond_if_else_store_replacement_1 (then_bb, else_bb, join_bb, |
2092 | then_store, else_store); | |
2093 | ok = ok || res; | |
2094 | } | |
2095 | ||
2096 | free_dependence_relations (then_ddrs); | |
2097 | free_dependence_relations (else_ddrs); | |
2473bfb7 | 2098 | free_data_refs (then_datarefs); |
2099 | free_data_refs (else_datarefs); | |
ec611e12 | 2100 | |
2101 | return ok; | |
2102 | } | |
2103 | ||
239e9670 | 2104 | /* Return TRUE if STMT has a VUSE whose corresponding VDEF is in BB. */ |
2105 | ||
2106 | static bool | |
42acab1c | 2107 | local_mem_dependence (gimple *stmt, basic_block bb) |
239e9670 | 2108 | { |
2109 | tree vuse = gimple_vuse (stmt); | |
42acab1c | 2110 | gimple *def; |
239e9670 | 2111 | |
2112 | if (!vuse) | |
2113 | return false; | |
2114 | ||
2115 | def = SSA_NAME_DEF_STMT (vuse); | |
2116 | return (def && gimple_bb (def) == bb); | |
2117 | } | |
2118 | ||
2119 | /* Given a "diamond" control-flow pattern where BB0 tests a condition, | |
2120 | BB1 and BB2 are "then" and "else" blocks dependent on this test, | |
f32420fb | 2121 | and BB3 rejoins control flow following BB1 and BB2, look for |
239e9670 | 2122 | opportunities to hoist loads as follows. If BB3 contains a PHI of |
2123 | two loads, one each occurring in BB1 and BB2, and the loads are | |
2124 | provably of adjacent fields in the same structure, then move both | |
2125 | loads into BB0. Of course this can only be done if there are no | |
2126 | dependencies preventing such motion. | |
2127 | ||
2128 | One of the hoisted loads will always be speculative, so the | |
2129 | transformation is currently conservative: | |
2130 | ||
2131 | - The fields must be strictly adjacent. | |
2132 | - The two fields must occupy a single memory block that is | |
2133 | guaranteed to not cross a page boundary. | |
2134 | ||
2135 | The last is difficult to prove, as such memory blocks should be | |
2136 | aligned on the minimum of the stack alignment boundary and the | |
2137 | alignment guaranteed by heap allocation interfaces. Thus we rely | |
2138 | on a parameter for the alignment value. | |
2139 | ||
2140 | Provided a good value is used for the last case, the first | |
2141 | restriction could possibly be relaxed. */ | |
2142 | ||
2143 | static void | |
2144 | hoist_adjacent_loads (basic_block bb0, basic_block bb1, | |
2145 | basic_block bb2, basic_block bb3) | |
2146 | { | |
2147 | int param_align = PARAM_VALUE (PARAM_L1_CACHE_LINE_SIZE); | |
2148 | unsigned param_align_bits = (unsigned) (param_align * BITS_PER_UNIT); | |
1a91d914 | 2149 | gphi_iterator gsi; |
239e9670 | 2150 | |
2151 | /* Walk the phis in bb3 looking for an opportunity. We are looking | |
2152 | for phis of two SSA names, one each of which is defined in bb1 and | |
2153 | bb2. */ | |
2154 | for (gsi = gsi_start_phis (bb3); !gsi_end_p (gsi); gsi_next (&gsi)) | |
2155 | { | |
1a91d914 | 2156 | gphi *phi_stmt = gsi.phi (); |
42acab1c | 2157 | gimple *def1, *def2; |
dfcf26a5 | 2158 | tree arg1, arg2, ref1, ref2, field1, field2; |
239e9670 | 2159 | tree tree_offset1, tree_offset2, tree_size2, next; |
2160 | int offset1, offset2, size2; | |
2161 | unsigned align1; | |
2162 | gimple_stmt_iterator gsi2; | |
2163 | basic_block bb_for_def1, bb_for_def2; | |
2164 | ||
7c782c9b | 2165 | if (gimple_phi_num_args (phi_stmt) != 2 |
2166 | || virtual_operand_p (gimple_phi_result (phi_stmt))) | |
239e9670 | 2167 | continue; |
2168 | ||
2169 | arg1 = gimple_phi_arg_def (phi_stmt, 0); | |
2170 | arg2 = gimple_phi_arg_def (phi_stmt, 1); | |
f32420fb | 2171 | |
239e9670 | 2172 | if (TREE_CODE (arg1) != SSA_NAME |
2173 | || TREE_CODE (arg2) != SSA_NAME | |
2174 | || SSA_NAME_IS_DEFAULT_DEF (arg1) | |
7c782c9b | 2175 | || SSA_NAME_IS_DEFAULT_DEF (arg2)) |
239e9670 | 2176 | continue; |
2177 | ||
2178 | def1 = SSA_NAME_DEF_STMT (arg1); | |
2179 | def2 = SSA_NAME_DEF_STMT (arg2); | |
2180 | ||
2181 | if ((gimple_bb (def1) != bb1 || gimple_bb (def2) != bb2) | |
2182 | && (gimple_bb (def2) != bb1 || gimple_bb (def1) != bb2)) | |
2183 | continue; | |
2184 | ||
2185 | /* Check the mode of the arguments to be sure a conditional move | |
2186 | can be generated for it. */ | |
935611bc | 2187 | if (optab_handler (movcc_optab, TYPE_MODE (TREE_TYPE (arg1))) |
2188 | == CODE_FOR_nothing) | |
239e9670 | 2189 | continue; |
2190 | ||
2191 | /* Both statements must be assignments whose RHS is a COMPONENT_REF. */ | |
2192 | if (!gimple_assign_single_p (def1) | |
6cc085b6 | 2193 | || !gimple_assign_single_p (def2) |
2194 | || gimple_has_volatile_ops (def1) | |
2195 | || gimple_has_volatile_ops (def2)) | |
239e9670 | 2196 | continue; |
2197 | ||
2198 | ref1 = gimple_assign_rhs1 (def1); | |
2199 | ref2 = gimple_assign_rhs1 (def2); | |
2200 | ||
2201 | if (TREE_CODE (ref1) != COMPONENT_REF | |
2202 | || TREE_CODE (ref2) != COMPONENT_REF) | |
2203 | continue; | |
2204 | ||
2205 | /* The zeroth operand of the two component references must be | |
2206 | identical. It is not sufficient to compare get_base_address of | |
2207 | the two references, because this could allow for different | |
2208 | elements of the same array in the two trees. It is not safe to | |
2209 | assume that the existence of one array element implies the | |
2210 | existence of a different one. */ | |
2211 | if (!operand_equal_p (TREE_OPERAND (ref1, 0), TREE_OPERAND (ref2, 0), 0)) | |
2212 | continue; | |
2213 | ||
2214 | field1 = TREE_OPERAND (ref1, 1); | |
2215 | field2 = TREE_OPERAND (ref2, 1); | |
2216 | ||
2217 | /* Check for field adjacency, and ensure field1 comes first. */ | |
2218 | for (next = DECL_CHAIN (field1); | |
2219 | next && TREE_CODE (next) != FIELD_DECL; | |
2220 | next = DECL_CHAIN (next)) | |
2221 | ; | |
2222 | ||
2223 | if (next != field2) | |
2224 | { | |
2225 | for (next = DECL_CHAIN (field2); | |
2226 | next && TREE_CODE (next) != FIELD_DECL; | |
2227 | next = DECL_CHAIN (next)) | |
2228 | ; | |
2229 | ||
2230 | if (next != field1) | |
2231 | continue; | |
2232 | ||
dfcf26a5 | 2233 | std::swap (field1, field2); |
2234 | std::swap (def1, def2); | |
239e9670 | 2235 | } |
2236 | ||
7c74ee50 | 2237 | bb_for_def1 = gimple_bb (def1); |
2238 | bb_for_def2 = gimple_bb (def2); | |
2239 | ||
239e9670 | 2240 | /* Check for proper alignment of the first field. */ |
2241 | tree_offset1 = bit_position (field1); | |
2242 | tree_offset2 = bit_position (field2); | |
2243 | tree_size2 = DECL_SIZE (field2); | |
2244 | ||
e913b5cd | 2245 | if (!tree_fits_uhwi_p (tree_offset1) |
2246 | || !tree_fits_uhwi_p (tree_offset2) | |
2247 | || !tree_fits_uhwi_p (tree_size2)) | |
239e9670 | 2248 | continue; |
2249 | ||
e913b5cd | 2250 | offset1 = tree_to_uhwi (tree_offset1); |
2251 | offset2 = tree_to_uhwi (tree_offset2); | |
2252 | size2 = tree_to_uhwi (tree_size2); | |
239e9670 | 2253 | align1 = DECL_ALIGN (field1) % param_align_bits; |
2254 | ||
2255 | if (offset1 % BITS_PER_UNIT != 0) | |
2256 | continue; | |
2257 | ||
2258 | /* For profitability, the two field references should fit within | |
2259 | a single cache line. */ | |
2260 | if (align1 + offset2 - offset1 + size2 > param_align_bits) | |
2261 | continue; | |
2262 | ||
2263 | /* The two expressions cannot be dependent upon vdefs defined | |
2264 | in bb1/bb2. */ | |
2265 | if (local_mem_dependence (def1, bb_for_def1) | |
2266 | || local_mem_dependence (def2, bb_for_def2)) | |
2267 | continue; | |
2268 | ||
2269 | /* The conditions are satisfied; hoist the loads from bb1 and bb2 into | |
2270 | bb0. We hoist the first one first so that a cache miss is handled | |
2271 | efficiently regardless of hardware cache-fill policy. */ | |
2272 | gsi2 = gsi_for_stmt (def1); | |
2273 | gsi_move_to_bb_end (&gsi2, bb0); | |
2274 | gsi2 = gsi_for_stmt (def2); | |
2275 | gsi_move_to_bb_end (&gsi2, bb0); | |
2276 | ||
2277 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2278 | { | |
2279 | fprintf (dump_file, | |
2280 | "\nHoisting adjacent loads from %d and %d into %d: \n", | |
2281 | bb_for_def1->index, bb_for_def2->index, bb0->index); | |
2282 | print_gimple_stmt (dump_file, def1, 0, TDF_VOPS|TDF_MEMSYMS); | |
2283 | print_gimple_stmt (dump_file, def2, 0, TDF_VOPS|TDF_MEMSYMS); | |
2284 | } | |
2285 | } | |
2286 | } | |
2287 | ||
2288 | /* Determine whether we should attempt to hoist adjacent loads out of | |
2289 | diamond patterns in pass_phiopt. Always hoist loads if | |
2290 | -fhoist-adjacent-loads is specified and the target machine has | |
6f0ddab1 | 2291 | both a conditional move instruction and a defined cache line size. */ |
239e9670 | 2292 | |
2293 | static bool | |
2294 | gate_hoist_loads (void) | |
2295 | { | |
6f0ddab1 | 2296 | return (flag_hoist_adjacent_loads == 1 |
2297 | && PARAM_VALUE (PARAM_L1_CACHE_LINE_SIZE) | |
2298 | && HAVE_conditional_move); | |
239e9670 | 2299 | } |
2300 | ||
65b0537f | 2301 | /* This pass tries to replaces an if-then-else block with an |
2302 | assignment. We have four kinds of transformations. Some of these | |
2303 | transformations are also performed by the ifcvt RTL optimizer. | |
2304 | ||
2305 | Conditional Replacement | |
2306 | ----------------------- | |
2307 | ||
2308 | This transformation, implemented in conditional_replacement, | |
2309 | replaces | |
2310 | ||
2311 | bb0: | |
2312 | if (cond) goto bb2; else goto bb1; | |
2313 | bb1: | |
2314 | bb2: | |
2315 | x = PHI <0 (bb1), 1 (bb0), ...>; | |
2316 | ||
2317 | with | |
2318 | ||
2319 | bb0: | |
2320 | x' = cond; | |
2321 | goto bb2; | |
2322 | bb2: | |
2323 | x = PHI <x' (bb0), ...>; | |
2324 | ||
2325 | We remove bb1 as it becomes unreachable. This occurs often due to | |
2326 | gimplification of conditionals. | |
2327 | ||
2328 | Value Replacement | |
2329 | ----------------- | |
2330 | ||
2331 | This transformation, implemented in value_replacement, replaces | |
2332 | ||
2333 | bb0: | |
2334 | if (a != b) goto bb2; else goto bb1; | |
2335 | bb1: | |
2336 | bb2: | |
2337 | x = PHI <a (bb1), b (bb0), ...>; | |
2338 | ||
2339 | with | |
2340 | ||
2341 | bb0: | |
2342 | bb2: | |
2343 | x = PHI <b (bb0), ...>; | |
2344 | ||
2345 | This opportunity can sometimes occur as a result of other | |
2346 | optimizations. | |
2347 | ||
2348 | ||
2349 | Another case caught by value replacement looks like this: | |
2350 | ||
2351 | bb0: | |
2352 | t1 = a == CONST; | |
2353 | t2 = b > c; | |
2354 | t3 = t1 & t2; | |
2355 | if (t3 != 0) goto bb1; else goto bb2; | |
2356 | bb1: | |
2357 | bb2: | |
2358 | x = PHI (CONST, a) | |
2359 | ||
2360 | Gets replaced with: | |
2361 | bb0: | |
2362 | bb2: | |
2363 | t1 = a == CONST; | |
2364 | t2 = b > c; | |
2365 | t3 = t1 & t2; | |
2366 | x = a; | |
2367 | ||
2368 | ABS Replacement | |
2369 | --------------- | |
2370 | ||
2371 | This transformation, implemented in abs_replacement, replaces | |
2372 | ||
2373 | bb0: | |
2374 | if (a >= 0) goto bb2; else goto bb1; | |
2375 | bb1: | |
2376 | x = -a; | |
2377 | bb2: | |
2378 | x = PHI <x (bb1), a (bb0), ...>; | |
2379 | ||
2380 | with | |
2381 | ||
2382 | bb0: | |
2383 | x' = ABS_EXPR< a >; | |
2384 | bb2: | |
2385 | x = PHI <x' (bb0), ...>; | |
2386 | ||
2387 | MIN/MAX Replacement | |
2388 | ------------------- | |
2389 | ||
2390 | This transformation, minmax_replacement replaces | |
2391 | ||
2392 | bb0: | |
2393 | if (a <= b) goto bb2; else goto bb1; | |
2394 | bb1: | |
2395 | bb2: | |
2396 | x = PHI <b (bb1), a (bb0), ...>; | |
2397 | ||
2398 | with | |
2399 | ||
2400 | bb0: | |
2401 | x' = MIN_EXPR (a, b) | |
2402 | bb2: | |
2403 | x = PHI <x' (bb0), ...>; | |
2404 | ||
2405 | A similar transformation is done for MAX_EXPR. | |
2406 | ||
2407 | ||
2408 | This pass also performs a fifth transformation of a slightly different | |
2409 | flavor. | |
2410 | ||
29a78fec | 2411 | Factor conversion in COND_EXPR |
2412 | ------------------------------ | |
2413 | ||
2414 | This transformation factors the conversion out of COND_EXPR with | |
2415 | factor_out_conditional_conversion. | |
2416 | ||
2417 | For example: | |
2418 | if (a <= CST) goto <bb 3>; else goto <bb 4>; | |
2419 | <bb 3>: | |
2420 | tmp = (int) a; | |
2421 | <bb 4>: | |
2422 | tmp = PHI <tmp, CST> | |
2423 | ||
2424 | Into: | |
2425 | if (a <= CST) goto <bb 3>; else goto <bb 4>; | |
2426 | <bb 3>: | |
2427 | <bb 4>: | |
2428 | a = PHI <a, CST> | |
2429 | tmp = (int) a; | |
2430 | ||
65b0537f | 2431 | Adjacent Load Hoisting |
2432 | ---------------------- | |
2433 | ||
2434 | This transformation replaces | |
2435 | ||
2436 | bb0: | |
2437 | if (...) goto bb2; else goto bb1; | |
2438 | bb1: | |
2439 | x1 = (<expr>).field1; | |
2440 | goto bb3; | |
2441 | bb2: | |
2442 | x2 = (<expr>).field2; | |
2443 | bb3: | |
2444 | # x = PHI <x1, x2>; | |
2445 | ||
2446 | with | |
2447 | ||
2448 | bb0: | |
2449 | x1 = (<expr>).field1; | |
2450 | x2 = (<expr>).field2; | |
2451 | if (...) goto bb2; else goto bb1; | |
2452 | bb1: | |
2453 | goto bb3; | |
2454 | bb2: | |
2455 | bb3: | |
2456 | # x = PHI <x1, x2>; | |
2457 | ||
2458 | The purpose of this transformation is to enable generation of conditional | |
2459 | move instructions such as Intel CMOVE or PowerPC ISEL. Because one of | |
2460 | the loads is speculative, the transformation is restricted to very | |
2461 | specific cases to avoid introducing a page fault. We are looking for | |
2462 | the common idiom: | |
2463 | ||
2464 | if (...) | |
2465 | x = y->left; | |
2466 | else | |
2467 | x = y->right; | |
2468 | ||
2469 | where left and right are typically adjacent pointers in a tree structure. */ | |
20e5647c | 2470 | |
cbe8bda8 | 2471 | namespace { |
2472 | ||
2473 | const pass_data pass_data_phiopt = | |
4ee9c684 | 2474 | { |
cbe8bda8 | 2475 | GIMPLE_PASS, /* type */ |
2476 | "phiopt", /* name */ | |
2477 | OPTGROUP_NONE, /* optinfo_flags */ | |
cbe8bda8 | 2478 | TV_TREE_PHIOPT, /* tv_id */ |
2479 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
2480 | 0, /* properties_provided */ | |
2481 | 0, /* properties_destroyed */ | |
2482 | 0, /* todo_flags_start */ | |
8b88439e | 2483 | 0, /* todo_flags_finish */ |
4ee9c684 | 2484 | }; |
e6d0e152 | 2485 | |
cbe8bda8 | 2486 | class pass_phiopt : public gimple_opt_pass |
2487 | { | |
2488 | public: | |
9af5ce0c | 2489 | pass_phiopt (gcc::context *ctxt) |
2490 | : gimple_opt_pass (pass_data_phiopt, ctxt) | |
cbe8bda8 | 2491 | {} |
2492 | ||
2493 | /* opt_pass methods: */ | |
ae84f584 | 2494 | opt_pass * clone () { return new pass_phiopt (m_ctxt); } |
3dac50cc | 2495 | virtual bool gate (function *) { return flag_ssa_phiopt; } |
65b0537f | 2496 | virtual unsigned int execute (function *) |
2497 | { | |
2498 | return tree_ssa_phiopt_worker (false, gate_hoist_loads ()); | |
2499 | } | |
cbe8bda8 | 2500 | |
2501 | }; // class pass_phiopt | |
2502 | ||
2503 | } // anon namespace | |
2504 | ||
2505 | gimple_opt_pass * | |
2506 | make_pass_phiopt (gcc::context *ctxt) | |
2507 | { | |
2508 | return new pass_phiopt (ctxt); | |
2509 | } | |
2510 | ||
cbe8bda8 | 2511 | namespace { |
2512 | ||
2513 | const pass_data pass_data_cselim = | |
e6d0e152 | 2514 | { |
cbe8bda8 | 2515 | GIMPLE_PASS, /* type */ |
2516 | "cselim", /* name */ | |
2517 | OPTGROUP_NONE, /* optinfo_flags */ | |
cbe8bda8 | 2518 | TV_TREE_PHIOPT, /* tv_id */ |
2519 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
2520 | 0, /* properties_provided */ | |
2521 | 0, /* properties_destroyed */ | |
2522 | 0, /* todo_flags_start */ | |
8b88439e | 2523 | 0, /* todo_flags_finish */ |
e6d0e152 | 2524 | }; |
cbe8bda8 | 2525 | |
2526 | class pass_cselim : public gimple_opt_pass | |
2527 | { | |
2528 | public: | |
9af5ce0c | 2529 | pass_cselim (gcc::context *ctxt) |
2530 | : gimple_opt_pass (pass_data_cselim, ctxt) | |
cbe8bda8 | 2531 | {} |
2532 | ||
2533 | /* opt_pass methods: */ | |
31315c24 | 2534 | virtual bool gate (function *) { return flag_tree_cselim; } |
65b0537f | 2535 | virtual unsigned int execute (function *) { return tree_ssa_cs_elim (); } |
cbe8bda8 | 2536 | |
2537 | }; // class pass_cselim | |
2538 | ||
2539 | } // anon namespace | |
2540 | ||
2541 | gimple_opt_pass * | |
2542 | make_pass_cselim (gcc::context *ctxt) | |
2543 | { | |
2544 | return new pass_cselim (ctxt); | |
2545 | } |