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1 | /* Vectorizer Specific Loop Manipulations |
2 | Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free Software | |
3 | Foundation, Inc. | |
4 | Contributed by Dorit Naishlos <dorit@il.ibm.com> | |
5 | and Ira Rosen <irar@il.ibm.com> | |
6 | ||
7 | This file is part of GCC. | |
8 | ||
9 | GCC is free software; you can redistribute it and/or modify it under | |
10 | the terms of the GNU General Public License as published by the Free | |
11 | Software Foundation; either version 3, or (at your option) any later | |
12 | version. | |
13 | ||
14 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
15 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
16 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
17 | for more details. | |
18 | ||
19 | You should have received a copy of the GNU General Public License | |
20 | along with GCC; see the file COPYING3. If not see | |
21 | <http://www.gnu.org/licenses/>. */ | |
22 | ||
23 | #include "config.h" | |
24 | #include "system.h" | |
25 | #include "coretypes.h" | |
26 | #include "tm.h" | |
27 | #include "ggc.h" | |
28 | #include "tree.h" | |
29 | #include "basic-block.h" | |
30 | #include "diagnostic.h" | |
31 | #include "tree-flow.h" | |
32 | #include "tree-dump.h" | |
33 | #include "cfgloop.h" | |
34 | #include "cfglayout.h" | |
35 | #include "expr.h" | |
36 | #include "toplev.h" | |
37 | #include "tree-scalar-evolution.h" | |
38 | #include "tree-vectorizer.h" | |
39 | #include "langhooks.h" | |
40 | ||
41 | /************************************************************************* | |
42 | Simple Loop Peeling Utilities | |
43 | ||
44 | Utilities to support loop peeling for vectorization purposes. | |
45 | *************************************************************************/ | |
46 | ||
47 | ||
48 | /* Renames the use *OP_P. */ | |
49 | ||
50 | static void | |
51 | rename_use_op (use_operand_p op_p) | |
52 | { | |
53 | tree new_name; | |
54 | ||
55 | if (TREE_CODE (USE_FROM_PTR (op_p)) != SSA_NAME) | |
56 | return; | |
57 | ||
58 | new_name = get_current_def (USE_FROM_PTR (op_p)); | |
59 | ||
60 | /* Something defined outside of the loop. */ | |
61 | if (!new_name) | |
62 | return; | |
63 | ||
64 | /* An ordinary ssa name defined in the loop. */ | |
65 | ||
66 | SET_USE (op_p, new_name); | |
67 | } | |
68 | ||
69 | ||
70 | /* Renames the variables in basic block BB. */ | |
71 | ||
72 | void | |
73 | rename_variables_in_bb (basic_block bb) | |
74 | { | |
75 | gimple_stmt_iterator gsi; | |
76 | gimple stmt; | |
77 | use_operand_p use_p; | |
78 | ssa_op_iter iter; | |
79 | edge e; | |
80 | edge_iterator ei; | |
81 | struct loop *loop = bb->loop_father; | |
82 | ||
83 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
84 | { | |
85 | stmt = gsi_stmt (gsi); | |
86 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES) | |
87 | rename_use_op (use_p); | |
88 | } | |
89 | ||
90 | FOR_EACH_EDGE (e, ei, bb->succs) | |
91 | { | |
92 | if (!flow_bb_inside_loop_p (loop, e->dest)) | |
93 | continue; | |
94 | for (gsi = gsi_start_phis (e->dest); !gsi_end_p (gsi); gsi_next (&gsi)) | |
95 | rename_use_op (PHI_ARG_DEF_PTR_FROM_EDGE (gsi_stmt (gsi), e)); | |
96 | } | |
97 | } | |
98 | ||
99 | ||
100 | /* Renames variables in new generated LOOP. */ | |
101 | ||
102 | void | |
103 | rename_variables_in_loop (struct loop *loop) | |
104 | { | |
105 | unsigned i; | |
106 | basic_block *bbs; | |
107 | ||
108 | bbs = get_loop_body (loop); | |
109 | ||
110 | for (i = 0; i < loop->num_nodes; i++) | |
111 | rename_variables_in_bb (bbs[i]); | |
112 | ||
113 | free (bbs); | |
114 | } | |
115 | ||
116 | ||
117 | /* Update the PHI nodes of NEW_LOOP. | |
118 | ||
119 | NEW_LOOP is a duplicate of ORIG_LOOP. | |
120 | AFTER indicates whether NEW_LOOP executes before or after ORIG_LOOP: | |
121 | AFTER is true if NEW_LOOP executes after ORIG_LOOP, and false if it | |
122 | executes before it. */ | |
123 | ||
124 | static void | |
125 | slpeel_update_phis_for_duplicate_loop (struct loop *orig_loop, | |
126 | struct loop *new_loop, bool after) | |
127 | { | |
128 | tree new_ssa_name; | |
129 | gimple phi_new, phi_orig; | |
130 | tree def; | |
131 | edge orig_loop_latch = loop_latch_edge (orig_loop); | |
132 | edge orig_entry_e = loop_preheader_edge (orig_loop); | |
133 | edge new_loop_exit_e = single_exit (new_loop); | |
134 | edge new_loop_entry_e = loop_preheader_edge (new_loop); | |
135 | edge entry_arg_e = (after ? orig_loop_latch : orig_entry_e); | |
136 | gimple_stmt_iterator gsi_new, gsi_orig; | |
137 | ||
138 | /* | |
139 | step 1. For each loop-header-phi: | |
140 | Add the first phi argument for the phi in NEW_LOOP | |
141 | (the one associated with the entry of NEW_LOOP) | |
142 | ||
143 | step 2. For each loop-header-phi: | |
144 | Add the second phi argument for the phi in NEW_LOOP | |
145 | (the one associated with the latch of NEW_LOOP) | |
146 | ||
147 | step 3. Update the phis in the successor block of NEW_LOOP. | |
148 | ||
149 | case 1: NEW_LOOP was placed before ORIG_LOOP: | |
150 | The successor block of NEW_LOOP is the header of ORIG_LOOP. | |
151 | Updating the phis in the successor block can therefore be done | |
152 | along with the scanning of the loop header phis, because the | |
153 | header blocks of ORIG_LOOP and NEW_LOOP have exactly the same | |
154 | phi nodes, organized in the same order. | |
155 | ||
156 | case 2: NEW_LOOP was placed after ORIG_LOOP: | |
157 | The successor block of NEW_LOOP is the original exit block of | |
158 | ORIG_LOOP - the phis to be updated are the loop-closed-ssa phis. | |
159 | We postpone updating these phis to a later stage (when | |
160 | loop guards are added). | |
161 | */ | |
162 | ||
163 | ||
164 | /* Scan the phis in the headers of the old and new loops | |
165 | (they are organized in exactly the same order). */ | |
166 | ||
167 | for (gsi_new = gsi_start_phis (new_loop->header), | |
168 | gsi_orig = gsi_start_phis (orig_loop->header); | |
169 | !gsi_end_p (gsi_new) && !gsi_end_p (gsi_orig); | |
170 | gsi_next (&gsi_new), gsi_next (&gsi_orig)) | |
171 | { | |
172 | phi_new = gsi_stmt (gsi_new); | |
173 | phi_orig = gsi_stmt (gsi_orig); | |
174 | ||
175 | /* step 1. */ | |
176 | def = PHI_ARG_DEF_FROM_EDGE (phi_orig, entry_arg_e); | |
177 | add_phi_arg (phi_new, def, new_loop_entry_e); | |
178 | ||
179 | /* step 2. */ | |
180 | def = PHI_ARG_DEF_FROM_EDGE (phi_orig, orig_loop_latch); | |
181 | if (TREE_CODE (def) != SSA_NAME) | |
182 | continue; | |
183 | ||
184 | new_ssa_name = get_current_def (def); | |
185 | if (!new_ssa_name) | |
186 | { | |
187 | /* This only happens if there are no definitions | |
188 | inside the loop. use the phi_result in this case. */ | |
189 | new_ssa_name = PHI_RESULT (phi_new); | |
190 | } | |
191 | ||
192 | /* An ordinary ssa name defined in the loop. */ | |
193 | add_phi_arg (phi_new, new_ssa_name, loop_latch_edge (new_loop)); | |
194 | ||
195 | /* step 3 (case 1). */ | |
196 | if (!after) | |
197 | { | |
198 | gcc_assert (new_loop_exit_e == orig_entry_e); | |
199 | SET_PHI_ARG_DEF (phi_orig, | |
200 | new_loop_exit_e->dest_idx, | |
201 | new_ssa_name); | |
202 | } | |
203 | } | |
204 | } | |
205 | ||
206 | ||
207 | /* Update PHI nodes for a guard of the LOOP. | |
208 | ||
209 | Input: | |
210 | - LOOP, GUARD_EDGE: LOOP is a loop for which we added guard code that | |
211 | controls whether LOOP is to be executed. GUARD_EDGE is the edge that | |
212 | originates from the guard-bb, skips LOOP and reaches the (unique) exit | |
213 | bb of LOOP. This loop-exit-bb is an empty bb with one successor. | |
214 | We denote this bb NEW_MERGE_BB because before the guard code was added | |
215 | it had a single predecessor (the LOOP header), and now it became a merge | |
216 | point of two paths - the path that ends with the LOOP exit-edge, and | |
217 | the path that ends with GUARD_EDGE. | |
218 | - NEW_EXIT_BB: New basic block that is added by this function between LOOP | |
219 | and NEW_MERGE_BB. It is used to place loop-closed-ssa-form exit-phis. | |
220 | ||
221 | ===> The CFG before the guard-code was added: | |
222 | LOOP_header_bb: | |
223 | loop_body | |
224 | if (exit_loop) goto update_bb | |
225 | else goto LOOP_header_bb | |
226 | update_bb: | |
227 | ||
228 | ==> The CFG after the guard-code was added: | |
229 | guard_bb: | |
230 | if (LOOP_guard_condition) goto new_merge_bb | |
231 | else goto LOOP_header_bb | |
232 | LOOP_header_bb: | |
233 | loop_body | |
234 | if (exit_loop_condition) goto new_merge_bb | |
235 | else goto LOOP_header_bb | |
236 | new_merge_bb: | |
237 | goto update_bb | |
238 | update_bb: | |
239 | ||
240 | ==> The CFG after this function: | |
241 | guard_bb: | |
242 | if (LOOP_guard_condition) goto new_merge_bb | |
243 | else goto LOOP_header_bb | |
244 | LOOP_header_bb: | |
245 | loop_body | |
246 | if (exit_loop_condition) goto new_exit_bb | |
247 | else goto LOOP_header_bb | |
248 | new_exit_bb: | |
249 | new_merge_bb: | |
250 | goto update_bb | |
251 | update_bb: | |
252 | ||
253 | This function: | |
254 | 1. creates and updates the relevant phi nodes to account for the new | |
255 | incoming edge (GUARD_EDGE) into NEW_MERGE_BB. This involves: | |
256 | 1.1. Create phi nodes at NEW_MERGE_BB. | |
257 | 1.2. Update the phi nodes at the successor of NEW_MERGE_BB (denoted | |
258 | UPDATE_BB). UPDATE_BB was the exit-bb of LOOP before NEW_MERGE_BB | |
259 | 2. preserves loop-closed-ssa-form by creating the required phi nodes | |
260 | at the exit of LOOP (i.e, in NEW_EXIT_BB). | |
261 | ||
262 | There are two flavors to this function: | |
263 | ||
264 | slpeel_update_phi_nodes_for_guard1: | |
265 | Here the guard controls whether we enter or skip LOOP, where LOOP is a | |
266 | prolog_loop (loop1 below), and the new phis created in NEW_MERGE_BB are | |
267 | for variables that have phis in the loop header. | |
268 | ||
269 | slpeel_update_phi_nodes_for_guard2: | |
270 | Here the guard controls whether we enter or skip LOOP, where LOOP is an | |
271 | epilog_loop (loop2 below), and the new phis created in NEW_MERGE_BB are | |
272 | for variables that have phis in the loop exit. | |
273 | ||
274 | I.E., the overall structure is: | |
275 | ||
276 | loop1_preheader_bb: | |
277 | guard1 (goto loop1/merge1_bb) | |
278 | loop1 | |
279 | loop1_exit_bb: | |
280 | guard2 (goto merge1_bb/merge2_bb) | |
281 | merge1_bb | |
282 | loop2 | |
283 | loop2_exit_bb | |
284 | merge2_bb | |
285 | next_bb | |
286 | ||
287 | slpeel_update_phi_nodes_for_guard1 takes care of creating phis in | |
288 | loop1_exit_bb and merge1_bb. These are entry phis (phis for the vars | |
289 | that have phis in loop1->header). | |
290 | ||
291 | slpeel_update_phi_nodes_for_guard2 takes care of creating phis in | |
292 | loop2_exit_bb and merge2_bb. These are exit phis (phis for the vars | |
293 | that have phis in next_bb). It also adds some of these phis to | |
294 | loop1_exit_bb. | |
295 | ||
296 | slpeel_update_phi_nodes_for_guard1 is always called before | |
297 | slpeel_update_phi_nodes_for_guard2. They are both needed in order | |
298 | to create correct data-flow and loop-closed-ssa-form. | |
299 | ||
300 | Generally slpeel_update_phi_nodes_for_guard1 creates phis for variables | |
301 | that change between iterations of a loop (and therefore have a phi-node | |
302 | at the loop entry), whereas slpeel_update_phi_nodes_for_guard2 creates | |
303 | phis for variables that are used out of the loop (and therefore have | |
304 | loop-closed exit phis). Some variables may be both updated between | |
305 | iterations and used after the loop. This is why in loop1_exit_bb we | |
306 | may need both entry_phis (created by slpeel_update_phi_nodes_for_guard1) | |
307 | and exit phis (created by slpeel_update_phi_nodes_for_guard2). | |
308 | ||
309 | - IS_NEW_LOOP: if IS_NEW_LOOP is true, then LOOP is a newly created copy of | |
310 | an original loop. i.e., we have: | |
311 | ||
312 | orig_loop | |
313 | guard_bb (goto LOOP/new_merge) | |
314 | new_loop <-- LOOP | |
315 | new_exit | |
316 | new_merge | |
317 | next_bb | |
318 | ||
319 | If IS_NEW_LOOP is false, then LOOP is an original loop, in which case we | |
320 | have: | |
321 | ||
322 | new_loop | |
323 | guard_bb (goto LOOP/new_merge) | |
324 | orig_loop <-- LOOP | |
325 | new_exit | |
326 | new_merge | |
327 | next_bb | |
328 | ||
329 | The SSA names defined in the original loop have a current | |
330 | reaching definition that that records the corresponding new | |
331 | ssa-name used in the new duplicated loop copy. | |
332 | */ | |
333 | ||
334 | /* Function slpeel_update_phi_nodes_for_guard1 | |
335 | ||
336 | Input: | |
337 | - GUARD_EDGE, LOOP, IS_NEW_LOOP, NEW_EXIT_BB - as explained above. | |
338 | - DEFS - a bitmap of ssa names to mark new names for which we recorded | |
339 | information. | |
340 | ||
341 | In the context of the overall structure, we have: | |
342 | ||
343 | loop1_preheader_bb: | |
344 | guard1 (goto loop1/merge1_bb) | |
345 | LOOP-> loop1 | |
346 | loop1_exit_bb: | |
347 | guard2 (goto merge1_bb/merge2_bb) | |
348 | merge1_bb | |
349 | loop2 | |
350 | loop2_exit_bb | |
351 | merge2_bb | |
352 | next_bb | |
353 | ||
354 | For each name updated between loop iterations (i.e - for each name that has | |
355 | an entry (loop-header) phi in LOOP) we create a new phi in: | |
356 | 1. merge1_bb (to account for the edge from guard1) | |
357 | 2. loop1_exit_bb (an exit-phi to keep LOOP in loop-closed form) | |
358 | */ | |
359 | ||
360 | static void | |
361 | slpeel_update_phi_nodes_for_guard1 (edge guard_edge, struct loop *loop, | |
362 | bool is_new_loop, basic_block *new_exit_bb, | |
363 | bitmap *defs) | |
364 | { | |
365 | gimple orig_phi, new_phi; | |
366 | gimple update_phi, update_phi2; | |
367 | tree guard_arg, loop_arg; | |
368 | basic_block new_merge_bb = guard_edge->dest; | |
369 | edge e = EDGE_SUCC (new_merge_bb, 0); | |
370 | basic_block update_bb = e->dest; | |
371 | basic_block orig_bb = loop->header; | |
372 | edge new_exit_e; | |
373 | tree current_new_name; | |
374 | tree name; | |
375 | gimple_stmt_iterator gsi_orig, gsi_update; | |
376 | ||
377 | /* Create new bb between loop and new_merge_bb. */ | |
378 | *new_exit_bb = split_edge (single_exit (loop)); | |
379 | ||
380 | new_exit_e = EDGE_SUCC (*new_exit_bb, 0); | |
381 | ||
382 | for (gsi_orig = gsi_start_phis (orig_bb), | |
383 | gsi_update = gsi_start_phis (update_bb); | |
384 | !gsi_end_p (gsi_orig) && !gsi_end_p (gsi_update); | |
385 | gsi_next (&gsi_orig), gsi_next (&gsi_update)) | |
386 | { | |
387 | orig_phi = gsi_stmt (gsi_orig); | |
388 | update_phi = gsi_stmt (gsi_update); | |
389 | ||
390 | /* Virtual phi; Mark it for renaming. We actually want to call | |
391 | mar_sym_for_renaming, but since all ssa renaming datastructures | |
392 | are going to be freed before we get to call ssa_update, we just | |
393 | record this name for now in a bitmap, and will mark it for | |
394 | renaming later. */ | |
395 | name = PHI_RESULT (orig_phi); | |
396 | if (!is_gimple_reg (SSA_NAME_VAR (name))) | |
397 | bitmap_set_bit (vect_memsyms_to_rename, DECL_UID (SSA_NAME_VAR (name))); | |
398 | ||
399 | /** 1. Handle new-merge-point phis **/ | |
400 | ||
401 | /* 1.1. Generate new phi node in NEW_MERGE_BB: */ | |
402 | new_phi = create_phi_node (SSA_NAME_VAR (PHI_RESULT (orig_phi)), | |
403 | new_merge_bb); | |
404 | ||
405 | /* 1.2. NEW_MERGE_BB has two incoming edges: GUARD_EDGE and the exit-edge | |
406 | of LOOP. Set the two phi args in NEW_PHI for these edges: */ | |
407 | loop_arg = PHI_ARG_DEF_FROM_EDGE (orig_phi, EDGE_SUCC (loop->latch, 0)); | |
408 | guard_arg = PHI_ARG_DEF_FROM_EDGE (orig_phi, loop_preheader_edge (loop)); | |
409 | ||
410 | add_phi_arg (new_phi, loop_arg, new_exit_e); | |
411 | add_phi_arg (new_phi, guard_arg, guard_edge); | |
412 | ||
413 | /* 1.3. Update phi in successor block. */ | |
414 | gcc_assert (PHI_ARG_DEF_FROM_EDGE (update_phi, e) == loop_arg | |
415 | || PHI_ARG_DEF_FROM_EDGE (update_phi, e) == guard_arg); | |
416 | SET_PHI_ARG_DEF (update_phi, e->dest_idx, PHI_RESULT (new_phi)); | |
417 | update_phi2 = new_phi; | |
418 | ||
419 | ||
420 | /** 2. Handle loop-closed-ssa-form phis **/ | |
421 | ||
422 | if (!is_gimple_reg (PHI_RESULT (orig_phi))) | |
423 | continue; | |
424 | ||
425 | /* 2.1. Generate new phi node in NEW_EXIT_BB: */ | |
426 | new_phi = create_phi_node (SSA_NAME_VAR (PHI_RESULT (orig_phi)), | |
427 | *new_exit_bb); | |
428 | ||
429 | /* 2.2. NEW_EXIT_BB has one incoming edge: the exit-edge of the loop. */ | |
430 | add_phi_arg (new_phi, loop_arg, single_exit (loop)); | |
431 | ||
432 | /* 2.3. Update phi in successor of NEW_EXIT_BB: */ | |
433 | gcc_assert (PHI_ARG_DEF_FROM_EDGE (update_phi2, new_exit_e) == loop_arg); | |
434 | SET_PHI_ARG_DEF (update_phi2, new_exit_e->dest_idx, PHI_RESULT (new_phi)); | |
435 | ||
436 | /* 2.4. Record the newly created name with set_current_def. | |
437 | We want to find a name such that | |
438 | name = get_current_def (orig_loop_name) | |
439 | and to set its current definition as follows: | |
440 | set_current_def (name, new_phi_name) | |
441 | ||
442 | If LOOP is a new loop then loop_arg is already the name we're | |
443 | looking for. If LOOP is the original loop, then loop_arg is | |
444 | the orig_loop_name and the relevant name is recorded in its | |
445 | current reaching definition. */ | |
446 | if (is_new_loop) | |
447 | current_new_name = loop_arg; | |
448 | else | |
449 | { | |
450 | current_new_name = get_current_def (loop_arg); | |
451 | /* current_def is not available only if the variable does not | |
452 | change inside the loop, in which case we also don't care | |
453 | about recording a current_def for it because we won't be | |
454 | trying to create loop-exit-phis for it. */ | |
455 | if (!current_new_name) | |
456 | continue; | |
457 | } | |
458 | gcc_assert (get_current_def (current_new_name) == NULL_TREE); | |
459 | ||
460 | set_current_def (current_new_name, PHI_RESULT (new_phi)); | |
461 | bitmap_set_bit (*defs, SSA_NAME_VERSION (current_new_name)); | |
462 | } | |
463 | } | |
464 | ||
465 | ||
466 | /* Function slpeel_update_phi_nodes_for_guard2 | |
467 | ||
468 | Input: | |
469 | - GUARD_EDGE, LOOP, IS_NEW_LOOP, NEW_EXIT_BB - as explained above. | |
470 | ||
471 | In the context of the overall structure, we have: | |
472 | ||
473 | loop1_preheader_bb: | |
474 | guard1 (goto loop1/merge1_bb) | |
475 | loop1 | |
476 | loop1_exit_bb: | |
477 | guard2 (goto merge1_bb/merge2_bb) | |
478 | merge1_bb | |
479 | LOOP-> loop2 | |
480 | loop2_exit_bb | |
481 | merge2_bb | |
482 | next_bb | |
483 | ||
484 | For each name used out side the loop (i.e - for each name that has an exit | |
485 | phi in next_bb) we create a new phi in: | |
486 | 1. merge2_bb (to account for the edge from guard_bb) | |
487 | 2. loop2_exit_bb (an exit-phi to keep LOOP in loop-closed form) | |
488 | 3. guard2 bb (an exit phi to keep the preceding loop in loop-closed form), | |
489 | if needed (if it wasn't handled by slpeel_update_phis_nodes_for_phi1). | |
490 | */ | |
491 | ||
492 | static void | |
493 | slpeel_update_phi_nodes_for_guard2 (edge guard_edge, struct loop *loop, | |
494 | bool is_new_loop, basic_block *new_exit_bb) | |
495 | { | |
496 | gimple orig_phi, new_phi; | |
497 | gimple update_phi, update_phi2; | |
498 | tree guard_arg, loop_arg; | |
499 | basic_block new_merge_bb = guard_edge->dest; | |
500 | edge e = EDGE_SUCC (new_merge_bb, 0); | |
501 | basic_block update_bb = e->dest; | |
502 | edge new_exit_e; | |
503 | tree orig_def, orig_def_new_name; | |
504 | tree new_name, new_name2; | |
505 | tree arg; | |
506 | gimple_stmt_iterator gsi; | |
507 | ||
508 | /* Create new bb between loop and new_merge_bb. */ | |
509 | *new_exit_bb = split_edge (single_exit (loop)); | |
510 | ||
511 | new_exit_e = EDGE_SUCC (*new_exit_bb, 0); | |
512 | ||
513 | for (gsi = gsi_start_phis (update_bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
514 | { | |
515 | update_phi = gsi_stmt (gsi); | |
516 | orig_phi = update_phi; | |
517 | orig_def = PHI_ARG_DEF_FROM_EDGE (orig_phi, e); | |
518 | /* This loop-closed-phi actually doesn't represent a use | |
519 | out of the loop - the phi arg is a constant. */ | |
520 | if (TREE_CODE (orig_def) != SSA_NAME) | |
521 | continue; | |
522 | orig_def_new_name = get_current_def (orig_def); | |
523 | arg = NULL_TREE; | |
524 | ||
525 | /** 1. Handle new-merge-point phis **/ | |
526 | ||
527 | /* 1.1. Generate new phi node in NEW_MERGE_BB: */ | |
528 | new_phi = create_phi_node (SSA_NAME_VAR (PHI_RESULT (orig_phi)), | |
529 | new_merge_bb); | |
530 | ||
531 | /* 1.2. NEW_MERGE_BB has two incoming edges: GUARD_EDGE and the exit-edge | |
532 | of LOOP. Set the two PHI args in NEW_PHI for these edges: */ | |
533 | new_name = orig_def; | |
534 | new_name2 = NULL_TREE; | |
535 | if (orig_def_new_name) | |
536 | { | |
537 | new_name = orig_def_new_name; | |
538 | /* Some variables have both loop-entry-phis and loop-exit-phis. | |
539 | Such variables were given yet newer names by phis placed in | |
540 | guard_bb by slpeel_update_phi_nodes_for_guard1. I.e: | |
541 | new_name2 = get_current_def (get_current_def (orig_name)). */ | |
542 | new_name2 = get_current_def (new_name); | |
543 | } | |
544 | ||
545 | if (is_new_loop) | |
546 | { | |
547 | guard_arg = orig_def; | |
548 | loop_arg = new_name; | |
549 | } | |
550 | else | |
551 | { | |
552 | guard_arg = new_name; | |
553 | loop_arg = orig_def; | |
554 | } | |
555 | if (new_name2) | |
556 | guard_arg = new_name2; | |
557 | ||
558 | add_phi_arg (new_phi, loop_arg, new_exit_e); | |
559 | add_phi_arg (new_phi, guard_arg, guard_edge); | |
560 | ||
561 | /* 1.3. Update phi in successor block. */ | |
562 | gcc_assert (PHI_ARG_DEF_FROM_EDGE (update_phi, e) == orig_def); | |
563 | SET_PHI_ARG_DEF (update_phi, e->dest_idx, PHI_RESULT (new_phi)); | |
564 | update_phi2 = new_phi; | |
565 | ||
566 | ||
567 | /** 2. Handle loop-closed-ssa-form phis **/ | |
568 | ||
569 | /* 2.1. Generate new phi node in NEW_EXIT_BB: */ | |
570 | new_phi = create_phi_node (SSA_NAME_VAR (PHI_RESULT (orig_phi)), | |
571 | *new_exit_bb); | |
572 | ||
573 | /* 2.2. NEW_EXIT_BB has one incoming edge: the exit-edge of the loop. */ | |
574 | add_phi_arg (new_phi, loop_arg, single_exit (loop)); | |
575 | ||
576 | /* 2.3. Update phi in successor of NEW_EXIT_BB: */ | |
577 | gcc_assert (PHI_ARG_DEF_FROM_EDGE (update_phi2, new_exit_e) == loop_arg); | |
578 | SET_PHI_ARG_DEF (update_phi2, new_exit_e->dest_idx, PHI_RESULT (new_phi)); | |
579 | ||
580 | ||
581 | /** 3. Handle loop-closed-ssa-form phis for first loop **/ | |
582 | ||
583 | /* 3.1. Find the relevant names that need an exit-phi in | |
584 | GUARD_BB, i.e. names for which | |
585 | slpeel_update_phi_nodes_for_guard1 had not already created a | |
586 | phi node. This is the case for names that are used outside | |
587 | the loop (and therefore need an exit phi) but are not updated | |
588 | across loop iterations (and therefore don't have a | |
589 | loop-header-phi). | |
590 | ||
591 | slpeel_update_phi_nodes_for_guard1 is responsible for | |
592 | creating loop-exit phis in GUARD_BB for names that have a | |
593 | loop-header-phi. When such a phi is created we also record | |
594 | the new name in its current definition. If this new name | |
595 | exists, then guard_arg was set to this new name (see 1.2 | |
596 | above). Therefore, if guard_arg is not this new name, this | |
597 | is an indication that an exit-phi in GUARD_BB was not yet | |
598 | created, so we take care of it here. */ | |
599 | if (guard_arg == new_name2) | |
600 | continue; | |
601 | arg = guard_arg; | |
602 | ||
603 | /* 3.2. Generate new phi node in GUARD_BB: */ | |
604 | new_phi = create_phi_node (SSA_NAME_VAR (PHI_RESULT (orig_phi)), | |
605 | guard_edge->src); | |
606 | ||
607 | /* 3.3. GUARD_BB has one incoming edge: */ | |
608 | gcc_assert (EDGE_COUNT (guard_edge->src->preds) == 1); | |
609 | add_phi_arg (new_phi, arg, EDGE_PRED (guard_edge->src, 0)); | |
610 | ||
611 | /* 3.4. Update phi in successor of GUARD_BB: */ | |
612 | gcc_assert (PHI_ARG_DEF_FROM_EDGE (update_phi2, guard_edge) | |
613 | == guard_arg); | |
614 | SET_PHI_ARG_DEF (update_phi2, guard_edge->dest_idx, PHI_RESULT (new_phi)); | |
615 | } | |
616 | } | |
617 | ||
618 | ||
619 | /* Make the LOOP iterate NITERS times. This is done by adding a new IV | |
620 | that starts at zero, increases by one and its limit is NITERS. | |
621 | ||
622 | Assumption: the exit-condition of LOOP is the last stmt in the loop. */ | |
623 | ||
624 | void | |
625 | slpeel_make_loop_iterate_ntimes (struct loop *loop, tree niters) | |
626 | { | |
627 | tree indx_before_incr, indx_after_incr; | |
628 | gimple cond_stmt; | |
629 | gimple orig_cond; | |
630 | edge exit_edge = single_exit (loop); | |
631 | gimple_stmt_iterator loop_cond_gsi; | |
632 | gimple_stmt_iterator incr_gsi; | |
633 | bool insert_after; | |
634 | tree init = build_int_cst (TREE_TYPE (niters), 0); | |
635 | tree step = build_int_cst (TREE_TYPE (niters), 1); | |
636 | LOC loop_loc; | |
637 | enum tree_code code; | |
638 | ||
639 | orig_cond = get_loop_exit_condition (loop); | |
640 | gcc_assert (orig_cond); | |
641 | loop_cond_gsi = gsi_for_stmt (orig_cond); | |
642 | ||
643 | standard_iv_increment_position (loop, &incr_gsi, &insert_after); | |
644 | create_iv (init, step, NULL_TREE, loop, | |
645 | &incr_gsi, insert_after, &indx_before_incr, &indx_after_incr); | |
646 | ||
647 | indx_after_incr = force_gimple_operand_gsi (&loop_cond_gsi, indx_after_incr, | |
648 | true, NULL_TREE, true, | |
649 | GSI_SAME_STMT); | |
650 | niters = force_gimple_operand_gsi (&loop_cond_gsi, niters, true, NULL_TREE, | |
651 | true, GSI_SAME_STMT); | |
652 | ||
653 | code = (exit_edge->flags & EDGE_TRUE_VALUE) ? GE_EXPR : LT_EXPR; | |
654 | cond_stmt = gimple_build_cond (code, indx_after_incr, niters, NULL_TREE, | |
655 | NULL_TREE); | |
656 | ||
657 | gsi_insert_before (&loop_cond_gsi, cond_stmt, GSI_SAME_STMT); | |
658 | ||
659 | /* Remove old loop exit test: */ | |
660 | gsi_remove (&loop_cond_gsi, true); | |
661 | ||
662 | loop_loc = find_loop_location (loop); | |
663 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
664 | { | |
665 | if (loop_loc != UNKNOWN_LOC) | |
666 | fprintf (dump_file, "\nloop at %s:%d: ", | |
667 | LOC_FILE (loop_loc), LOC_LINE (loop_loc)); | |
668 | print_gimple_stmt (dump_file, cond_stmt, 0, TDF_SLIM); | |
669 | } | |
670 | ||
671 | loop->nb_iterations = niters; | |
672 | } | |
673 | ||
674 | ||
675 | /* Given LOOP this function generates a new copy of it and puts it | |
676 | on E which is either the entry or exit of LOOP. */ | |
677 | ||
678 | struct loop * | |
679 | slpeel_tree_duplicate_loop_to_edge_cfg (struct loop *loop, edge e) | |
680 | { | |
681 | struct loop *new_loop; | |
682 | basic_block *new_bbs, *bbs; | |
683 | bool at_exit; | |
684 | bool was_imm_dom; | |
685 | basic_block exit_dest; | |
686 | gimple phi; | |
687 | tree phi_arg; | |
688 | edge exit, new_exit; | |
689 | gimple_stmt_iterator gsi; | |
690 | ||
691 | at_exit = (e == single_exit (loop)); | |
692 | if (!at_exit && e != loop_preheader_edge (loop)) | |
693 | return NULL; | |
694 | ||
695 | bbs = get_loop_body (loop); | |
696 | ||
697 | /* Check whether duplication is possible. */ | |
698 | if (!can_copy_bbs_p (bbs, loop->num_nodes)) | |
699 | { | |
700 | free (bbs); | |
701 | return NULL; | |
702 | } | |
703 | ||
704 | /* Generate new loop structure. */ | |
705 | new_loop = duplicate_loop (loop, loop_outer (loop)); | |
706 | if (!new_loop) | |
707 | { | |
708 | free (bbs); | |
709 | return NULL; | |
710 | } | |
711 | ||
712 | exit_dest = single_exit (loop)->dest; | |
713 | was_imm_dom = (get_immediate_dominator (CDI_DOMINATORS, | |
714 | exit_dest) == loop->header ? | |
715 | true : false); | |
716 | ||
717 | new_bbs = XNEWVEC (basic_block, loop->num_nodes); | |
718 | ||
719 | exit = single_exit (loop); | |
720 | copy_bbs (bbs, loop->num_nodes, new_bbs, | |
721 | &exit, 1, &new_exit, NULL, | |
722 | e->src); | |
723 | ||
724 | /* Duplicating phi args at exit bbs as coming | |
725 | also from exit of duplicated loop. */ | |
726 | for (gsi = gsi_start_phis (exit_dest); !gsi_end_p (gsi); gsi_next (&gsi)) | |
727 | { | |
728 | phi = gsi_stmt (gsi); | |
729 | phi_arg = PHI_ARG_DEF_FROM_EDGE (phi, single_exit (loop)); | |
730 | if (phi_arg) | |
731 | { | |
732 | edge new_loop_exit_edge; | |
733 | ||
734 | if (EDGE_SUCC (new_loop->header, 0)->dest == new_loop->latch) | |
735 | new_loop_exit_edge = EDGE_SUCC (new_loop->header, 1); | |
736 | else | |
737 | new_loop_exit_edge = EDGE_SUCC (new_loop->header, 0); | |
738 | ||
739 | add_phi_arg (phi, phi_arg, new_loop_exit_edge); | |
740 | } | |
741 | } | |
742 | ||
743 | if (at_exit) /* Add the loop copy at exit. */ | |
744 | { | |
745 | redirect_edge_and_branch_force (e, new_loop->header); | |
746 | PENDING_STMT (e) = NULL; | |
747 | set_immediate_dominator (CDI_DOMINATORS, new_loop->header, e->src); | |
748 | if (was_imm_dom) | |
749 | set_immediate_dominator (CDI_DOMINATORS, exit_dest, new_loop->header); | |
750 | } | |
751 | else /* Add the copy at entry. */ | |
752 | { | |
753 | edge new_exit_e; | |
754 | edge entry_e = loop_preheader_edge (loop); | |
755 | basic_block preheader = entry_e->src; | |
756 | ||
757 | if (!flow_bb_inside_loop_p (new_loop, | |
758 | EDGE_SUCC (new_loop->header, 0)->dest)) | |
759 | new_exit_e = EDGE_SUCC (new_loop->header, 0); | |
760 | else | |
761 | new_exit_e = EDGE_SUCC (new_loop->header, 1); | |
762 | ||
763 | redirect_edge_and_branch_force (new_exit_e, loop->header); | |
764 | PENDING_STMT (new_exit_e) = NULL; | |
765 | set_immediate_dominator (CDI_DOMINATORS, loop->header, | |
766 | new_exit_e->src); | |
767 | ||
768 | /* We have to add phi args to the loop->header here as coming | |
769 | from new_exit_e edge. */ | |
770 | for (gsi = gsi_start_phis (loop->header); | |
771 | !gsi_end_p (gsi); | |
772 | gsi_next (&gsi)) | |
773 | { | |
774 | phi = gsi_stmt (gsi); | |
775 | phi_arg = PHI_ARG_DEF_FROM_EDGE (phi, entry_e); | |
776 | if (phi_arg) | |
777 | add_phi_arg (phi, phi_arg, new_exit_e); | |
778 | } | |
779 | ||
780 | redirect_edge_and_branch_force (entry_e, new_loop->header); | |
781 | PENDING_STMT (entry_e) = NULL; | |
782 | set_immediate_dominator (CDI_DOMINATORS, new_loop->header, preheader); | |
783 | } | |
784 | ||
785 | free (new_bbs); | |
786 | free (bbs); | |
787 | ||
788 | return new_loop; | |
789 | } | |
790 | ||
791 | ||
792 | /* Given the condition statement COND, put it as the last statement | |
793 | of GUARD_BB; EXIT_BB is the basic block to skip the loop; | |
794 | Assumes that this is the single exit of the guarded loop. | |
795 | Returns the skip edge. */ | |
796 | ||
797 | static edge | |
798 | slpeel_add_loop_guard (basic_block guard_bb, tree cond, basic_block exit_bb, | |
799 | basic_block dom_bb) | |
800 | { | |
801 | gimple_stmt_iterator gsi; | |
802 | edge new_e, enter_e; | |
803 | gimple cond_stmt; | |
804 | gimple_seq gimplify_stmt_list = NULL; | |
805 | ||
806 | enter_e = EDGE_SUCC (guard_bb, 0); | |
807 | enter_e->flags &= ~EDGE_FALLTHRU; | |
808 | enter_e->flags |= EDGE_FALSE_VALUE; | |
809 | gsi = gsi_last_bb (guard_bb); | |
810 | ||
811 | cond = force_gimple_operand (cond, &gimplify_stmt_list, true, NULL_TREE); | |
812 | cond_stmt = gimple_build_cond (NE_EXPR, | |
813 | cond, build_int_cst (TREE_TYPE (cond), 0), | |
814 | NULL_TREE, NULL_TREE); | |
815 | if (gimplify_stmt_list) | |
816 | gsi_insert_seq_after (&gsi, gimplify_stmt_list, GSI_NEW_STMT); | |
817 | ||
818 | gsi = gsi_last_bb (guard_bb); | |
819 | gsi_insert_after (&gsi, cond_stmt, GSI_NEW_STMT); | |
820 | ||
821 | /* Add new edge to connect guard block to the merge/loop-exit block. */ | |
822 | new_e = make_edge (guard_bb, exit_bb, EDGE_TRUE_VALUE); | |
823 | set_immediate_dominator (CDI_DOMINATORS, exit_bb, dom_bb); | |
824 | return new_e; | |
825 | } | |
826 | ||
827 | ||
828 | /* This function verifies that the following restrictions apply to LOOP: | |
829 | (1) it is innermost | |
830 | (2) it consists of exactly 2 basic blocks - header, and an empty latch. | |
831 | (3) it is single entry, single exit | |
832 | (4) its exit condition is the last stmt in the header | |
833 | (5) E is the entry/exit edge of LOOP. | |
834 | */ | |
835 | ||
836 | bool | |
837 | slpeel_can_duplicate_loop_p (const struct loop *loop, const_edge e) | |
838 | { | |
839 | edge exit_e = single_exit (loop); | |
840 | edge entry_e = loop_preheader_edge (loop); | |
841 | gimple orig_cond = get_loop_exit_condition (loop); | |
842 | gimple_stmt_iterator loop_exit_gsi = gsi_last_bb (exit_e->src); | |
843 | ||
844 | if (need_ssa_update_p ()) | |
845 | return false; | |
846 | ||
847 | if (loop->inner | |
848 | /* All loops have an outer scope; the only case loop->outer is NULL is for | |
849 | the function itself. */ | |
850 | || !loop_outer (loop) | |
851 | || loop->num_nodes != 2 | |
852 | || !empty_block_p (loop->latch) | |
853 | || !single_exit (loop) | |
854 | /* Verify that new loop exit condition can be trivially modified. */ | |
855 | || (!orig_cond || orig_cond != gsi_stmt (loop_exit_gsi)) | |
856 | || (e != exit_e && e != entry_e)) | |
857 | return false; | |
858 | ||
859 | return true; | |
860 | } | |
861 | ||
862 | #ifdef ENABLE_CHECKING | |
863 | static void | |
864 | slpeel_verify_cfg_after_peeling (struct loop *first_loop, | |
865 | struct loop *second_loop) | |
866 | { | |
867 | basic_block loop1_exit_bb = single_exit (first_loop)->dest; | |
868 | basic_block loop2_entry_bb = loop_preheader_edge (second_loop)->src; | |
869 | basic_block loop1_entry_bb = loop_preheader_edge (first_loop)->src; | |
870 | ||
871 | /* A guard that controls whether the second_loop is to be executed or skipped | |
872 | is placed in first_loop->exit. first_loop->exit therefore has two | |
873 | successors - one is the preheader of second_loop, and the other is a bb | |
874 | after second_loop. | |
875 | */ | |
876 | gcc_assert (EDGE_COUNT (loop1_exit_bb->succs) == 2); | |
877 | ||
878 | /* 1. Verify that one of the successors of first_loop->exit is the preheader | |
879 | of second_loop. */ | |
880 | ||
881 | /* The preheader of new_loop is expected to have two predecessors: | |
882 | first_loop->exit and the block that precedes first_loop. */ | |
883 | ||
884 | gcc_assert (EDGE_COUNT (loop2_entry_bb->preds) == 2 | |
885 | && ((EDGE_PRED (loop2_entry_bb, 0)->src == loop1_exit_bb | |
886 | && EDGE_PRED (loop2_entry_bb, 1)->src == loop1_entry_bb) | |
887 | || (EDGE_PRED (loop2_entry_bb, 1)->src == loop1_exit_bb | |
888 | && EDGE_PRED (loop2_entry_bb, 0)->src == loop1_entry_bb))); | |
889 | ||
890 | /* Verify that the other successor of first_loop->exit is after the | |
891 | second_loop. */ | |
892 | /* TODO */ | |
893 | } | |
894 | #endif | |
895 | ||
896 | /* If the run time cost model check determines that vectorization is | |
897 | not profitable and hence scalar loop should be generated then set | |
898 | FIRST_NITERS to prologue peeled iterations. This will allow all the | |
899 | iterations to be executed in the prologue peeled scalar loop. */ | |
900 | ||
901 | static void | |
902 | set_prologue_iterations (basic_block bb_before_first_loop, | |
903 | tree first_niters, | |
904 | struct loop *loop, | |
905 | unsigned int th) | |
906 | { | |
907 | edge e; | |
908 | basic_block cond_bb, then_bb; | |
909 | tree var, prologue_after_cost_adjust_name; | |
910 | gimple_stmt_iterator gsi; | |
911 | gimple newphi; | |
912 | edge e_true, e_false, e_fallthru; | |
913 | gimple cond_stmt; | |
914 | gimple_seq gimplify_stmt_list = NULL, stmts = NULL; | |
915 | tree cost_pre_condition = NULL_TREE; | |
916 | tree scalar_loop_iters = | |
917 | unshare_expr (LOOP_VINFO_NITERS_UNCHANGED (loop_vec_info_for_loop (loop))); | |
918 | ||
919 | e = single_pred_edge (bb_before_first_loop); | |
920 | cond_bb = split_edge(e); | |
921 | ||
922 | e = single_pred_edge (bb_before_first_loop); | |
923 | then_bb = split_edge(e); | |
924 | set_immediate_dominator (CDI_DOMINATORS, then_bb, cond_bb); | |
925 | ||
926 | e_false = make_single_succ_edge (cond_bb, bb_before_first_loop, | |
927 | EDGE_FALSE_VALUE); | |
928 | set_immediate_dominator (CDI_DOMINATORS, bb_before_first_loop, cond_bb); | |
929 | ||
930 | e_true = EDGE_PRED (then_bb, 0); | |
931 | e_true->flags &= ~EDGE_FALLTHRU; | |
932 | e_true->flags |= EDGE_TRUE_VALUE; | |
933 | ||
934 | e_fallthru = EDGE_SUCC (then_bb, 0); | |
935 | ||
936 | cost_pre_condition = | |
937 | fold_build2 (LE_EXPR, boolean_type_node, scalar_loop_iters, | |
938 | build_int_cst (TREE_TYPE (scalar_loop_iters), th)); | |
939 | cost_pre_condition = | |
940 | force_gimple_operand (cost_pre_condition, &gimplify_stmt_list, | |
941 | true, NULL_TREE); | |
942 | cond_stmt = gimple_build_cond (NE_EXPR, cost_pre_condition, | |
943 | build_int_cst (TREE_TYPE (cost_pre_condition), | |
944 | 0), NULL_TREE, NULL_TREE); | |
945 | ||
946 | gsi = gsi_last_bb (cond_bb); | |
947 | if (gimplify_stmt_list) | |
948 | gsi_insert_seq_after (&gsi, gimplify_stmt_list, GSI_NEW_STMT); | |
949 | ||
950 | gsi = gsi_last_bb (cond_bb); | |
951 | gsi_insert_after (&gsi, cond_stmt, GSI_NEW_STMT); | |
952 | ||
953 | var = create_tmp_var (TREE_TYPE (scalar_loop_iters), | |
954 | "prologue_after_cost_adjust"); | |
955 | add_referenced_var (var); | |
956 | prologue_after_cost_adjust_name = | |
957 | force_gimple_operand (scalar_loop_iters, &stmts, false, var); | |
958 | ||
959 | gsi = gsi_last_bb (then_bb); | |
960 | if (stmts) | |
961 | gsi_insert_seq_after (&gsi, stmts, GSI_NEW_STMT); | |
962 | ||
963 | newphi = create_phi_node (var, bb_before_first_loop); | |
964 | add_phi_arg (newphi, prologue_after_cost_adjust_name, e_fallthru); | |
965 | add_phi_arg (newphi, first_niters, e_false); | |
966 | ||
967 | first_niters = PHI_RESULT (newphi); | |
968 | } | |
969 | ||
970 | ||
971 | /* Function slpeel_tree_peel_loop_to_edge. | |
972 | ||
973 | Peel the first (last) iterations of LOOP into a new prolog (epilog) loop | |
974 | that is placed on the entry (exit) edge E of LOOP. After this transformation | |
975 | we have two loops one after the other - first-loop iterates FIRST_NITERS | |
976 | times, and second-loop iterates the remainder NITERS - FIRST_NITERS times. | |
977 | If the cost model indicates that it is profitable to emit a scalar | |
978 | loop instead of the vector one, then the prolog (epilog) loop will iterate | |
979 | for the entire unchanged scalar iterations of the loop. | |
980 | ||
981 | Input: | |
982 | - LOOP: the loop to be peeled. | |
983 | - E: the exit or entry edge of LOOP. | |
984 | If it is the entry edge, we peel the first iterations of LOOP. In this | |
985 | case first-loop is LOOP, and second-loop is the newly created loop. | |
986 | If it is the exit edge, we peel the last iterations of LOOP. In this | |
987 | case, first-loop is the newly created loop, and second-loop is LOOP. | |
988 | - NITERS: the number of iterations that LOOP iterates. | |
989 | - FIRST_NITERS: the number of iterations that the first-loop should iterate. | |
990 | - UPDATE_FIRST_LOOP_COUNT: specified whether this function is responsible | |
991 | for updating the loop bound of the first-loop to FIRST_NITERS. If it | |
992 | is false, the caller of this function may want to take care of this | |
993 | (this can be useful if we don't want new stmts added to first-loop). | |
994 | - TH: cost model profitability threshold of iterations for vectorization. | |
995 | - CHECK_PROFITABILITY: specify whether cost model check has not occurred | |
996 | during versioning and hence needs to occur during | |
997 | prologue generation or whether cost model check | |
998 | has not occurred during prologue generation and hence | |
999 | needs to occur during epilogue generation. | |
1000 | ||
1001 | ||
1002 | Output: | |
1003 | The function returns a pointer to the new loop-copy, or NULL if it failed | |
1004 | to perform the transformation. | |
1005 | ||
1006 | The function generates two if-then-else guards: one before the first loop, | |
1007 | and the other before the second loop: | |
1008 | The first guard is: | |
1009 | if (FIRST_NITERS == 0) then skip the first loop, | |
1010 | and go directly to the second loop. | |
1011 | The second guard is: | |
1012 | if (FIRST_NITERS == NITERS) then skip the second loop. | |
1013 | ||
1014 | FORNOW only simple loops are supported (see slpeel_can_duplicate_loop_p). | |
1015 | FORNOW the resulting code will not be in loop-closed-ssa form. | |
1016 | */ | |
1017 | ||
1018 | static struct loop* | |
1019 | slpeel_tree_peel_loop_to_edge (struct loop *loop, | |
1020 | edge e, tree first_niters, | |
1021 | tree niters, bool update_first_loop_count, | |
1022 | unsigned int th, bool check_profitability) | |
1023 | { | |
1024 | struct loop *new_loop = NULL, *first_loop, *second_loop; | |
1025 | edge skip_e; | |
1026 | tree pre_condition = NULL_TREE; | |
1027 | bitmap definitions; | |
1028 | basic_block bb_before_second_loop, bb_after_second_loop; | |
1029 | basic_block bb_before_first_loop; | |
1030 | basic_block bb_between_loops; | |
1031 | basic_block new_exit_bb; | |
1032 | edge exit_e = single_exit (loop); | |
1033 | LOC loop_loc; | |
1034 | tree cost_pre_condition = NULL_TREE; | |
1035 | ||
1036 | if (!slpeel_can_duplicate_loop_p (loop, e)) | |
1037 | return NULL; | |
1038 | ||
1039 | /* We have to initialize cfg_hooks. Then, when calling | |
1040 | cfg_hooks->split_edge, the function tree_split_edge | |
1041 | is actually called and, when calling cfg_hooks->duplicate_block, | |
1042 | the function tree_duplicate_bb is called. */ | |
1043 | gimple_register_cfg_hooks (); | |
1044 | ||
1045 | ||
1046 | /* 1. Generate a copy of LOOP and put it on E (E is the entry/exit of LOOP). | |
1047 | Resulting CFG would be: | |
1048 | ||
1049 | first_loop: | |
1050 | do { | |
1051 | } while ... | |
1052 | ||
1053 | second_loop: | |
1054 | do { | |
1055 | } while ... | |
1056 | ||
1057 | orig_exit_bb: | |
1058 | */ | |
1059 | ||
1060 | if (!(new_loop = slpeel_tree_duplicate_loop_to_edge_cfg (loop, e))) | |
1061 | { | |
1062 | loop_loc = find_loop_location (loop); | |
1063 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1064 | { | |
1065 | if (loop_loc != UNKNOWN_LOC) | |
1066 | fprintf (dump_file, "\n%s:%d: note: ", | |
1067 | LOC_FILE (loop_loc), LOC_LINE (loop_loc)); | |
1068 | fprintf (dump_file, "tree_duplicate_loop_to_edge_cfg failed.\n"); | |
1069 | } | |
1070 | return NULL; | |
1071 | } | |
1072 | ||
1073 | if (e == exit_e) | |
1074 | { | |
1075 | /* NEW_LOOP was placed after LOOP. */ | |
1076 | first_loop = loop; | |
1077 | second_loop = new_loop; | |
1078 | } | |
1079 | else | |
1080 | { | |
1081 | /* NEW_LOOP was placed before LOOP. */ | |
1082 | first_loop = new_loop; | |
1083 | second_loop = loop; | |
1084 | } | |
1085 | ||
1086 | definitions = ssa_names_to_replace (); | |
1087 | slpeel_update_phis_for_duplicate_loop (loop, new_loop, e == exit_e); | |
1088 | rename_variables_in_loop (new_loop); | |
1089 | ||
1090 | ||
1091 | /* 2. Add the guard code in one of the following ways: | |
1092 | ||
1093 | 2.a Add the guard that controls whether the first loop is executed. | |
1094 | This occurs when this function is invoked for prologue or epilogue | |
1095 | generation and when the cost model check can be done at compile time. | |
1096 | ||
1097 | Resulting CFG would be: | |
1098 | ||
1099 | bb_before_first_loop: | |
1100 | if (FIRST_NITERS == 0) GOTO bb_before_second_loop | |
1101 | GOTO first-loop | |
1102 | ||
1103 | first_loop: | |
1104 | do { | |
1105 | } while ... | |
1106 | ||
1107 | bb_before_second_loop: | |
1108 | ||
1109 | second_loop: | |
1110 | do { | |
1111 | } while ... | |
1112 | ||
1113 | orig_exit_bb: | |
1114 | ||
1115 | 2.b Add the cost model check that allows the prologue | |
1116 | to iterate for the entire unchanged scalar | |
1117 | iterations of the loop in the event that the cost | |
1118 | model indicates that the scalar loop is more | |
1119 | profitable than the vector one. This occurs when | |
1120 | this function is invoked for prologue generation | |
1121 | and the cost model check needs to be done at run | |
1122 | time. | |
1123 | ||
1124 | Resulting CFG after prologue peeling would be: | |
1125 | ||
1126 | if (scalar_loop_iterations <= th) | |
1127 | FIRST_NITERS = scalar_loop_iterations | |
1128 | ||
1129 | bb_before_first_loop: | |
1130 | if (FIRST_NITERS == 0) GOTO bb_before_second_loop | |
1131 | GOTO first-loop | |
1132 | ||
1133 | first_loop: | |
1134 | do { | |
1135 | } while ... | |
1136 | ||
1137 | bb_before_second_loop: | |
1138 | ||
1139 | second_loop: | |
1140 | do { | |
1141 | } while ... | |
1142 | ||
1143 | orig_exit_bb: | |
1144 | ||
1145 | 2.c Add the cost model check that allows the epilogue | |
1146 | to iterate for the entire unchanged scalar | |
1147 | iterations of the loop in the event that the cost | |
1148 | model indicates that the scalar loop is more | |
1149 | profitable than the vector one. This occurs when | |
1150 | this function is invoked for epilogue generation | |
1151 | and the cost model check needs to be done at run | |
1152 | time. | |
1153 | ||
1154 | Resulting CFG after prologue peeling would be: | |
1155 | ||
1156 | bb_before_first_loop: | |
1157 | if ((scalar_loop_iterations <= th) | |
1158 | || | |
1159 | FIRST_NITERS == 0) GOTO bb_before_second_loop | |
1160 | GOTO first-loop | |
1161 | ||
1162 | first_loop: | |
1163 | do { | |
1164 | } while ... | |
1165 | ||
1166 | bb_before_second_loop: | |
1167 | ||
1168 | second_loop: | |
1169 | do { | |
1170 | } while ... | |
1171 | ||
1172 | orig_exit_bb: | |
1173 | */ | |
1174 | ||
1175 | bb_before_first_loop = split_edge (loop_preheader_edge (first_loop)); | |
1176 | bb_before_second_loop = split_edge (single_exit (first_loop)); | |
1177 | ||
1178 | /* Epilogue peeling. */ | |
1179 | if (!update_first_loop_count) | |
1180 | { | |
1181 | pre_condition = | |
1182 | fold_build2 (LE_EXPR, boolean_type_node, first_niters, | |
1183 | build_int_cst (TREE_TYPE (first_niters), 0)); | |
1184 | if (check_profitability) | |
1185 | { | |
1186 | tree scalar_loop_iters | |
1187 | = unshare_expr (LOOP_VINFO_NITERS_UNCHANGED | |
1188 | (loop_vec_info_for_loop (loop))); | |
1189 | cost_pre_condition = | |
1190 | fold_build2 (LE_EXPR, boolean_type_node, scalar_loop_iters, | |
1191 | build_int_cst (TREE_TYPE (scalar_loop_iters), th)); | |
1192 | ||
1193 | pre_condition = fold_build2 (TRUTH_OR_EXPR, boolean_type_node, | |
1194 | cost_pre_condition, pre_condition); | |
1195 | } | |
1196 | } | |
1197 | ||
1198 | /* Prologue peeling. */ | |
1199 | else | |
1200 | { | |
1201 | if (check_profitability) | |
1202 | set_prologue_iterations (bb_before_first_loop, first_niters, | |
1203 | loop, th); | |
1204 | ||
1205 | pre_condition = | |
1206 | fold_build2 (LE_EXPR, boolean_type_node, first_niters, | |
1207 | build_int_cst (TREE_TYPE (first_niters), 0)); | |
1208 | } | |
1209 | ||
1210 | skip_e = slpeel_add_loop_guard (bb_before_first_loop, pre_condition, | |
1211 | bb_before_second_loop, bb_before_first_loop); | |
1212 | slpeel_update_phi_nodes_for_guard1 (skip_e, first_loop, | |
1213 | first_loop == new_loop, | |
1214 | &new_exit_bb, &definitions); | |
1215 | ||
1216 | ||
1217 | /* 3. Add the guard that controls whether the second loop is executed. | |
1218 | Resulting CFG would be: | |
1219 | ||
1220 | bb_before_first_loop: | |
1221 | if (FIRST_NITERS == 0) GOTO bb_before_second_loop (skip first loop) | |
1222 | GOTO first-loop | |
1223 | ||
1224 | first_loop: | |
1225 | do { | |
1226 | } while ... | |
1227 | ||
1228 | bb_between_loops: | |
1229 | if (FIRST_NITERS == NITERS) GOTO bb_after_second_loop (skip second loop) | |
1230 | GOTO bb_before_second_loop | |
1231 | ||
1232 | bb_before_second_loop: | |
1233 | ||
1234 | second_loop: | |
1235 | do { | |
1236 | } while ... | |
1237 | ||
1238 | bb_after_second_loop: | |
1239 | ||
1240 | orig_exit_bb: | |
1241 | */ | |
1242 | ||
1243 | bb_between_loops = new_exit_bb; | |
1244 | bb_after_second_loop = split_edge (single_exit (second_loop)); | |
1245 | ||
1246 | pre_condition = | |
1247 | fold_build2 (EQ_EXPR, boolean_type_node, first_niters, niters); | |
1248 | skip_e = slpeel_add_loop_guard (bb_between_loops, pre_condition, | |
1249 | bb_after_second_loop, bb_before_first_loop); | |
1250 | slpeel_update_phi_nodes_for_guard2 (skip_e, second_loop, | |
1251 | second_loop == new_loop, &new_exit_bb); | |
1252 | ||
1253 | /* 4. Make first-loop iterate FIRST_NITERS times, if requested. | |
1254 | */ | |
1255 | if (update_first_loop_count) | |
1256 | slpeel_make_loop_iterate_ntimes (first_loop, first_niters); | |
1257 | ||
1258 | BITMAP_FREE (definitions); | |
1259 | delete_update_ssa (); | |
1260 | ||
1261 | return new_loop; | |
1262 | } | |
1263 | ||
1264 | /* Function vect_get_loop_location. | |
1265 | ||
1266 | Extract the location of the loop in the source code. | |
1267 | If the loop is not well formed for vectorization, an estimated | |
1268 | location is calculated. | |
1269 | Return the loop location if succeed and NULL if not. */ | |
1270 | ||
1271 | LOC | |
1272 | find_loop_location (struct loop *loop) | |
1273 | { | |
1274 | gimple stmt = NULL; | |
1275 | basic_block bb; | |
1276 | gimple_stmt_iterator si; | |
1277 | ||
1278 | if (!loop) | |
1279 | return UNKNOWN_LOC; | |
1280 | ||
1281 | stmt = get_loop_exit_condition (loop); | |
1282 | ||
1283 | if (stmt && gimple_location (stmt) != UNKNOWN_LOC) | |
1284 | return gimple_location (stmt); | |
1285 | ||
1286 | /* If we got here the loop is probably not "well formed", | |
1287 | try to estimate the loop location */ | |
1288 | ||
1289 | if (!loop->header) | |
1290 | return UNKNOWN_LOC; | |
1291 | ||
1292 | bb = loop->header; | |
1293 | ||
1294 | for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si)) | |
1295 | { | |
1296 | stmt = gsi_stmt (si); | |
1297 | if (gimple_location (stmt) != UNKNOWN_LOC) | |
1298 | return gimple_location (stmt); | |
1299 | } | |
1300 | ||
1301 | return UNKNOWN_LOC; | |
1302 | } | |
1303 | ||
1304 | ||
1305 | /* This function builds ni_name = number of iterations loop executes | |
1306 | on the loop preheader. */ | |
1307 | ||
1308 | static tree | |
1309 | vect_build_loop_niters (loop_vec_info loop_vinfo) | |
1310 | { | |
1311 | tree ni_name, var; | |
1312 | gimple_seq stmts = NULL; | |
1313 | edge pe; | |
1314 | struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); | |
1315 | tree ni = unshare_expr (LOOP_VINFO_NITERS (loop_vinfo)); | |
1316 | ||
1317 | var = create_tmp_var (TREE_TYPE (ni), "niters"); | |
1318 | add_referenced_var (var); | |
1319 | ni_name = force_gimple_operand (ni, &stmts, false, var); | |
1320 | ||
1321 | pe = loop_preheader_edge (loop); | |
1322 | if (stmts) | |
1323 | { | |
1324 | basic_block new_bb = gsi_insert_seq_on_edge_immediate (pe, stmts); | |
1325 | gcc_assert (!new_bb); | |
1326 | } | |
1327 | ||
1328 | return ni_name; | |
1329 | } | |
1330 | ||
1331 | ||
1332 | /* This function generates the following statements: | |
1333 | ||
1334 | ni_name = number of iterations loop executes | |
1335 | ratio = ni_name / vf | |
1336 | ratio_mult_vf_name = ratio * vf | |
1337 | ||
1338 | and places them at the loop preheader edge. */ | |
1339 | ||
1340 | static void | |
1341 | vect_generate_tmps_on_preheader (loop_vec_info loop_vinfo, | |
1342 | tree *ni_name_ptr, | |
1343 | tree *ratio_mult_vf_name_ptr, | |
1344 | tree *ratio_name_ptr) | |
1345 | { | |
1346 | ||
1347 | edge pe; | |
1348 | basic_block new_bb; | |
1349 | gimple_seq stmts; | |
1350 | tree ni_name; | |
1351 | tree var; | |
1352 | tree ratio_name; | |
1353 | tree ratio_mult_vf_name; | |
1354 | struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); | |
1355 | tree ni = LOOP_VINFO_NITERS (loop_vinfo); | |
1356 | int vf = LOOP_VINFO_VECT_FACTOR (loop_vinfo); | |
1357 | tree log_vf; | |
1358 | ||
1359 | pe = loop_preheader_edge (loop); | |
1360 | ||
1361 | /* Generate temporary variable that contains | |
1362 | number of iterations loop executes. */ | |
1363 | ||
1364 | ni_name = vect_build_loop_niters (loop_vinfo); | |
1365 | log_vf = build_int_cst (TREE_TYPE (ni), exact_log2 (vf)); | |
1366 | ||
1367 | /* Create: ratio = ni >> log2(vf) */ | |
1368 | ||
1369 | ratio_name = fold_build2 (RSHIFT_EXPR, TREE_TYPE (ni_name), ni_name, log_vf); | |
1370 | if (!is_gimple_val (ratio_name)) | |
1371 | { | |
1372 | var = create_tmp_var (TREE_TYPE (ni), "bnd"); | |
1373 | add_referenced_var (var); | |
1374 | ||
1375 | stmts = NULL; | |
1376 | ratio_name = force_gimple_operand (ratio_name, &stmts, true, var); | |
1377 | pe = loop_preheader_edge (loop); | |
1378 | new_bb = gsi_insert_seq_on_edge_immediate (pe, stmts); | |
1379 | gcc_assert (!new_bb); | |
1380 | } | |
1381 | ||
1382 | /* Create: ratio_mult_vf = ratio << log2 (vf). */ | |
1383 | ||
1384 | ratio_mult_vf_name = fold_build2 (LSHIFT_EXPR, TREE_TYPE (ratio_name), | |
1385 | ratio_name, log_vf); | |
1386 | if (!is_gimple_val (ratio_mult_vf_name)) | |
1387 | { | |
1388 | var = create_tmp_var (TREE_TYPE (ni), "ratio_mult_vf"); | |
1389 | add_referenced_var (var); | |
1390 | ||
1391 | stmts = NULL; | |
1392 | ratio_mult_vf_name = force_gimple_operand (ratio_mult_vf_name, &stmts, | |
1393 | true, var); | |
1394 | pe = loop_preheader_edge (loop); | |
1395 | new_bb = gsi_insert_seq_on_edge_immediate (pe, stmts); | |
1396 | gcc_assert (!new_bb); | |
1397 | } | |
1398 | ||
1399 | *ni_name_ptr = ni_name; | |
1400 | *ratio_mult_vf_name_ptr = ratio_mult_vf_name; | |
1401 | *ratio_name_ptr = ratio_name; | |
1402 | ||
1403 | return; | |
1404 | } | |
1405 | ||
1406 | /* Function vect_can_advance_ivs_p | |
1407 | ||
1408 | In case the number of iterations that LOOP iterates is unknown at compile | |
1409 | time, an epilog loop will be generated, and the loop induction variables | |
1410 | (IVs) will be "advanced" to the value they are supposed to take just before | |
1411 | the epilog loop. Here we check that the access function of the loop IVs | |
1412 | and the expression that represents the loop bound are simple enough. | |
1413 | These restrictions will be relaxed in the future. */ | |
1414 | ||
1415 | bool | |
1416 | vect_can_advance_ivs_p (loop_vec_info loop_vinfo) | |
1417 | { | |
1418 | struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); | |
1419 | basic_block bb = loop->header; | |
1420 | gimple phi; | |
1421 | gimple_stmt_iterator gsi; | |
1422 | ||
1423 | /* Analyze phi functions of the loop header. */ | |
1424 | ||
1425 | if (vect_print_dump_info (REPORT_DETAILS)) | |
1426 | fprintf (vect_dump, "vect_can_advance_ivs_p:"); | |
1427 | ||
1428 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
1429 | { | |
1430 | tree access_fn = NULL; | |
1431 | tree evolution_part; | |
1432 | ||
1433 | phi = gsi_stmt (gsi); | |
1434 | if (vect_print_dump_info (REPORT_DETAILS)) | |
1435 | { | |
1436 | fprintf (vect_dump, "Analyze phi: "); | |
1437 | print_gimple_stmt (vect_dump, phi, 0, TDF_SLIM); | |
1438 | } | |
1439 | ||
1440 | /* Skip virtual phi's. The data dependences that are associated with | |
1441 | virtual defs/uses (i.e., memory accesses) are analyzed elsewhere. */ | |
1442 | ||
1443 | if (!is_gimple_reg (SSA_NAME_VAR (PHI_RESULT (phi)))) | |
1444 | { | |
1445 | if (vect_print_dump_info (REPORT_DETAILS)) | |
1446 | fprintf (vect_dump, "virtual phi. skip."); | |
1447 | continue; | |
1448 | } | |
1449 | ||
1450 | /* Skip reduction phis. */ | |
1451 | ||
1452 | if (STMT_VINFO_DEF_TYPE (vinfo_for_stmt (phi)) == vect_reduction_def) | |
1453 | { | |
1454 | if (vect_print_dump_info (REPORT_DETAILS)) | |
1455 | fprintf (vect_dump, "reduc phi. skip."); | |
1456 | continue; | |
1457 | } | |
1458 | ||
1459 | /* Analyze the evolution function. */ | |
1460 | ||
1461 | access_fn = instantiate_parameters | |
1462 | (loop, analyze_scalar_evolution (loop, PHI_RESULT (phi))); | |
1463 | ||
1464 | if (!access_fn) | |
1465 | { | |
1466 | if (vect_print_dump_info (REPORT_DETAILS)) | |
1467 | fprintf (vect_dump, "No Access function."); | |
1468 | return false; | |
1469 | } | |
1470 | ||
1471 | if (vect_print_dump_info (REPORT_DETAILS)) | |
1472 | { | |
1473 | fprintf (vect_dump, "Access function of PHI: "); | |
1474 | print_generic_expr (vect_dump, access_fn, TDF_SLIM); | |
1475 | } | |
1476 | ||
1477 | evolution_part = evolution_part_in_loop_num (access_fn, loop->num); | |
1478 | ||
1479 | if (evolution_part == NULL_TREE) | |
1480 | { | |
1481 | if (vect_print_dump_info (REPORT_DETAILS)) | |
1482 | fprintf (vect_dump, "No evolution."); | |
1483 | return false; | |
1484 | } | |
1485 | ||
1486 | /* FORNOW: We do not transform initial conditions of IVs | |
1487 | which evolution functions are a polynomial of degree >= 2. */ | |
1488 | ||
1489 | if (tree_is_chrec (evolution_part)) | |
1490 | return false; | |
1491 | } | |
1492 | ||
1493 | return true; | |
1494 | } | |
1495 | ||
1496 | ||
1497 | /* Function vect_update_ivs_after_vectorizer. | |
1498 | ||
1499 | "Advance" the induction variables of LOOP to the value they should take | |
1500 | after the execution of LOOP. This is currently necessary because the | |
1501 | vectorizer does not handle induction variables that are used after the | |
1502 | loop. Such a situation occurs when the last iterations of LOOP are | |
1503 | peeled, because: | |
1504 | 1. We introduced new uses after LOOP for IVs that were not originally used | |
1505 | after LOOP: the IVs of LOOP are now used by an epilog loop. | |
1506 | 2. LOOP is going to be vectorized; this means that it will iterate N/VF | |
1507 | times, whereas the loop IVs should be bumped N times. | |
1508 | ||
1509 | Input: | |
1510 | - LOOP - a loop that is going to be vectorized. The last few iterations | |
1511 | of LOOP were peeled. | |
1512 | - NITERS - the number of iterations that LOOP executes (before it is | |
1513 | vectorized). i.e, the number of times the ivs should be bumped. | |
1514 | - UPDATE_E - a successor edge of LOOP->exit that is on the (only) path | |
1515 | coming out from LOOP on which there are uses of the LOOP ivs | |
1516 | (this is the path from LOOP->exit to epilog_loop->preheader). | |
1517 | ||
1518 | The new definitions of the ivs are placed in LOOP->exit. | |
1519 | The phi args associated with the edge UPDATE_E in the bb | |
1520 | UPDATE_E->dest are updated accordingly. | |
1521 | ||
1522 | Assumption 1: Like the rest of the vectorizer, this function assumes | |
1523 | a single loop exit that has a single predecessor. | |
1524 | ||
1525 | Assumption 2: The phi nodes in the LOOP header and in update_bb are | |
1526 | organized in the same order. | |
1527 | ||
1528 | Assumption 3: The access function of the ivs is simple enough (see | |
1529 | vect_can_advance_ivs_p). This assumption will be relaxed in the future. | |
1530 | ||
1531 | Assumption 4: Exactly one of the successors of LOOP exit-bb is on a path | |
1532 | coming out of LOOP on which the ivs of LOOP are used (this is the path | |
1533 | that leads to the epilog loop; other paths skip the epilog loop). This | |
1534 | path starts with the edge UPDATE_E, and its destination (denoted update_bb) | |
1535 | needs to have its phis updated. | |
1536 | */ | |
1537 | ||
1538 | static void | |
1539 | vect_update_ivs_after_vectorizer (loop_vec_info loop_vinfo, tree niters, | |
1540 | edge update_e) | |
1541 | { | |
1542 | struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); | |
1543 | basic_block exit_bb = single_exit (loop)->dest; | |
1544 | gimple phi, phi1; | |
1545 | gimple_stmt_iterator gsi, gsi1; | |
1546 | basic_block update_bb = update_e->dest; | |
1547 | ||
1548 | /* gcc_assert (vect_can_advance_ivs_p (loop_vinfo)); */ | |
1549 | ||
1550 | /* Make sure there exists a single-predecessor exit bb: */ | |
1551 | gcc_assert (single_pred_p (exit_bb)); | |
1552 | ||
1553 | for (gsi = gsi_start_phis (loop->header), gsi1 = gsi_start_phis (update_bb); | |
1554 | !gsi_end_p (gsi) && !gsi_end_p (gsi1); | |
1555 | gsi_next (&gsi), gsi_next (&gsi1)) | |
1556 | { | |
1557 | tree access_fn = NULL; | |
1558 | tree evolution_part; | |
1559 | tree init_expr; | |
1560 | tree step_expr; | |
1561 | tree var, ni, ni_name; | |
1562 | gimple_stmt_iterator last_gsi; | |
1563 | ||
1564 | phi = gsi_stmt (gsi); | |
1565 | phi1 = gsi_stmt (gsi1); | |
1566 | if (vect_print_dump_info (REPORT_DETAILS)) | |
1567 | { | |
1568 | fprintf (vect_dump, "vect_update_ivs_after_vectorizer: phi: "); | |
1569 | print_gimple_stmt (vect_dump, phi, 0, TDF_SLIM); | |
1570 | } | |
1571 | ||
1572 | /* Skip virtual phi's. */ | |
1573 | if (!is_gimple_reg (SSA_NAME_VAR (PHI_RESULT (phi)))) | |
1574 | { | |
1575 | if (vect_print_dump_info (REPORT_DETAILS)) | |
1576 | fprintf (vect_dump, "virtual phi. skip."); | |
1577 | continue; | |
1578 | } | |
1579 | ||
1580 | /* Skip reduction phis. */ | |
1581 | if (STMT_VINFO_DEF_TYPE (vinfo_for_stmt (phi)) == vect_reduction_def) | |
1582 | { | |
1583 | if (vect_print_dump_info (REPORT_DETAILS)) | |
1584 | fprintf (vect_dump, "reduc phi. skip."); | |
1585 | continue; | |
1586 | } | |
1587 | ||
1588 | access_fn = analyze_scalar_evolution (loop, PHI_RESULT (phi)); | |
1589 | gcc_assert (access_fn); | |
1590 | STRIP_NOPS (access_fn); | |
1591 | evolution_part = | |
1592 | unshare_expr (evolution_part_in_loop_num (access_fn, loop->num)); | |
1593 | gcc_assert (evolution_part != NULL_TREE); | |
1594 | ||
1595 | /* FORNOW: We do not support IVs whose evolution function is a polynomial | |
1596 | of degree >= 2 or exponential. */ | |
1597 | gcc_assert (!tree_is_chrec (evolution_part)); | |
1598 | ||
1599 | step_expr = evolution_part; | |
1600 | init_expr = unshare_expr (initial_condition_in_loop_num (access_fn, | |
1601 | loop->num)); | |
1602 | ||
1603 | if (POINTER_TYPE_P (TREE_TYPE (init_expr))) | |
1604 | ni = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (init_expr), | |
1605 | init_expr, | |
1606 | fold_convert (sizetype, | |
1607 | fold_build2 (MULT_EXPR, TREE_TYPE (niters), | |
1608 | niters, step_expr))); | |
1609 | else | |
1610 | ni = fold_build2 (PLUS_EXPR, TREE_TYPE (init_expr), | |
1611 | fold_build2 (MULT_EXPR, TREE_TYPE (init_expr), | |
1612 | fold_convert (TREE_TYPE (init_expr), | |
1613 | niters), | |
1614 | step_expr), | |
1615 | init_expr); | |
1616 | ||
1617 | ||
1618 | ||
1619 | var = create_tmp_var (TREE_TYPE (init_expr), "tmp"); | |
1620 | add_referenced_var (var); | |
1621 | ||
1622 | last_gsi = gsi_last_bb (exit_bb); | |
1623 | ni_name = force_gimple_operand_gsi (&last_gsi, ni, false, var, | |
1624 | true, GSI_SAME_STMT); | |
1625 | ||
1626 | /* Fix phi expressions in the successor bb. */ | |
1627 | SET_PHI_ARG_DEF (phi1, update_e->dest_idx, ni_name); | |
1628 | } | |
1629 | } | |
1630 | ||
1631 | /* Return the more conservative threshold between the | |
1632 | min_profitable_iters returned by the cost model and the user | |
1633 | specified threshold, if provided. */ | |
1634 | ||
1635 | static unsigned int | |
1636 | conservative_cost_threshold (loop_vec_info loop_vinfo, | |
1637 | int min_profitable_iters) | |
1638 | { | |
1639 | unsigned int th; | |
1640 | int min_scalar_loop_bound; | |
1641 | ||
1642 | min_scalar_loop_bound = ((PARAM_VALUE (PARAM_MIN_VECT_LOOP_BOUND) | |
1643 | * LOOP_VINFO_VECT_FACTOR (loop_vinfo)) - 1); | |
1644 | ||
1645 | /* Use the cost model only if it is more conservative than user specified | |
1646 | threshold. */ | |
1647 | th = (unsigned) min_scalar_loop_bound; | |
1648 | if (min_profitable_iters | |
1649 | && (!min_scalar_loop_bound | |
1650 | || min_profitable_iters > min_scalar_loop_bound)) | |
1651 | th = (unsigned) min_profitable_iters; | |
1652 | ||
1653 | if (th && vect_print_dump_info (REPORT_COST)) | |
1654 | fprintf (vect_dump, "Vectorization may not be profitable."); | |
1655 | ||
1656 | return th; | |
1657 | } | |
1658 | ||
1659 | /* Function vect_do_peeling_for_loop_bound | |
1660 | ||
1661 | Peel the last iterations of the loop represented by LOOP_VINFO. | |
1662 | The peeled iterations form a new epilog loop. Given that the loop now | |
1663 | iterates NITERS times, the new epilog loop iterates | |
1664 | NITERS % VECTORIZATION_FACTOR times. | |
1665 | ||
1666 | The original loop will later be made to iterate | |
1667 | NITERS / VECTORIZATION_FACTOR times (this value is placed into RATIO). */ | |
1668 | ||
1669 | void | |
1670 | vect_do_peeling_for_loop_bound (loop_vec_info loop_vinfo, tree *ratio) | |
1671 | { | |
1672 | tree ni_name, ratio_mult_vf_name; | |
1673 | struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); | |
1674 | struct loop *new_loop; | |
1675 | edge update_e; | |
1676 | basic_block preheader; | |
1677 | int loop_num; | |
1678 | bool check_profitability = false; | |
1679 | unsigned int th = 0; | |
1680 | int min_profitable_iters; | |
1681 | ||
1682 | if (vect_print_dump_info (REPORT_DETAILS)) | |
1683 | fprintf (vect_dump, "=== vect_do_peeling_for_loop_bound ==="); | |
1684 | ||
1685 | initialize_original_copy_tables (); | |
1686 | ||
1687 | /* Generate the following variables on the preheader of original loop: | |
1688 | ||
1689 | ni_name = number of iteration the original loop executes | |
1690 | ratio = ni_name / vf | |
1691 | ratio_mult_vf_name = ratio * vf */ | |
1692 | vect_generate_tmps_on_preheader (loop_vinfo, &ni_name, | |
1693 | &ratio_mult_vf_name, ratio); | |
1694 | ||
1695 | loop_num = loop->num; | |
1696 | ||
1697 | /* If cost model check not done during versioning and | |
1698 | peeling for alignment. */ | |
1699 | if (!VEC_length (gimple, LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo)) | |
1700 | && !VEC_length (ddr_p, LOOP_VINFO_MAY_ALIAS_DDRS (loop_vinfo)) | |
1701 | && !LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo)) | |
1702 | { | |
1703 | check_profitability = true; | |
1704 | ||
1705 | /* Get profitability threshold for vectorized loop. */ | |
1706 | min_profitable_iters = LOOP_VINFO_COST_MODEL_MIN_ITERS (loop_vinfo); | |
1707 | ||
1708 | th = conservative_cost_threshold (loop_vinfo, | |
1709 | min_profitable_iters); | |
1710 | } | |
1711 | ||
1712 | new_loop = slpeel_tree_peel_loop_to_edge (loop, single_exit (loop), | |
1713 | ratio_mult_vf_name, ni_name, false, | |
1714 | th, check_profitability); | |
1715 | gcc_assert (new_loop); | |
1716 | gcc_assert (loop_num == loop->num); | |
1717 | #ifdef ENABLE_CHECKING | |
1718 | slpeel_verify_cfg_after_peeling (loop, new_loop); | |
1719 | #endif | |
1720 | ||
1721 | /* A guard that controls whether the new_loop is to be executed or skipped | |
1722 | is placed in LOOP->exit. LOOP->exit therefore has two successors - one | |
1723 | is the preheader of NEW_LOOP, where the IVs from LOOP are used. The other | |
1724 | is a bb after NEW_LOOP, where these IVs are not used. Find the edge that | |
1725 | is on the path where the LOOP IVs are used and need to be updated. */ | |
1726 | ||
1727 | preheader = loop_preheader_edge (new_loop)->src; | |
1728 | if (EDGE_PRED (preheader, 0)->src == single_exit (loop)->dest) | |
1729 | update_e = EDGE_PRED (preheader, 0); | |
1730 | else | |
1731 | update_e = EDGE_PRED (preheader, 1); | |
1732 | ||
1733 | /* Update IVs of original loop as if they were advanced | |
1734 | by ratio_mult_vf_name steps. */ | |
1735 | vect_update_ivs_after_vectorizer (loop_vinfo, ratio_mult_vf_name, update_e); | |
1736 | ||
1737 | /* After peeling we have to reset scalar evolution analyzer. */ | |
1738 | scev_reset (); | |
1739 | ||
1740 | free_original_copy_tables (); | |
1741 | } | |
1742 | ||
1743 | ||
1744 | /* Function vect_gen_niters_for_prolog_loop | |
1745 | ||
1746 | Set the number of iterations for the loop represented by LOOP_VINFO | |
1747 | to the minimum between LOOP_NITERS (the original iteration count of the loop) | |
1748 | and the misalignment of DR - the data reference recorded in | |
1749 | LOOP_VINFO_UNALIGNED_DR (LOOP_VINFO). As a result, after the execution of | |
1750 | this loop, the data reference DR will refer to an aligned location. | |
1751 | ||
1752 | The following computation is generated: | |
1753 | ||
1754 | If the misalignment of DR is known at compile time: | |
1755 | addr_mis = int mis = DR_MISALIGNMENT (dr); | |
1756 | Else, compute address misalignment in bytes: | |
1757 | addr_mis = addr & (vectype_size - 1) | |
1758 | ||
1759 | prolog_niters = min (LOOP_NITERS, ((VF - addr_mis/elem_size)&(VF-1))/step) | |
1760 | ||
1761 | (elem_size = element type size; an element is the scalar element whose type | |
1762 | is the inner type of the vectype) | |
1763 | ||
1764 | When the step of the data-ref in the loop is not 1 (as in interleaved data | |
1765 | and SLP), the number of iterations of the prolog must be divided by the step | |
1766 | (which is equal to the size of interleaved group). | |
1767 | ||
1768 | The above formulas assume that VF == number of elements in the vector. This | |
1769 | may not hold when there are multiple-types in the loop. | |
1770 | In this case, for some data-references in the loop the VF does not represent | |
1771 | the number of elements that fit in the vector. Therefore, instead of VF we | |
1772 | use TYPE_VECTOR_SUBPARTS. */ | |
1773 | ||
1774 | static tree | |
1775 | vect_gen_niters_for_prolog_loop (loop_vec_info loop_vinfo, tree loop_niters) | |
1776 | { | |
1777 | struct data_reference *dr = LOOP_VINFO_UNALIGNED_DR (loop_vinfo); | |
1778 | struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); | |
1779 | tree var; | |
1780 | gimple_seq stmts; | |
1781 | tree iters, iters_name; | |
1782 | edge pe; | |
1783 | basic_block new_bb; | |
1784 | gimple dr_stmt = DR_STMT (dr); | |
1785 | stmt_vec_info stmt_info = vinfo_for_stmt (dr_stmt); | |
1786 | tree vectype = STMT_VINFO_VECTYPE (stmt_info); | |
1787 | int vectype_align = TYPE_ALIGN (vectype) / BITS_PER_UNIT; | |
1788 | tree niters_type = TREE_TYPE (loop_niters); | |
1789 | int step = 1; | |
1790 | int element_size = GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dr)))); | |
1791 | int nelements = TYPE_VECTOR_SUBPARTS (vectype); | |
1792 | ||
1793 | if (STMT_VINFO_STRIDED_ACCESS (stmt_info)) | |
1794 | step = DR_GROUP_SIZE (vinfo_for_stmt (DR_GROUP_FIRST_DR (stmt_info))); | |
1795 | ||
1796 | pe = loop_preheader_edge (loop); | |
1797 | ||
1798 | if (LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo) > 0) | |
1799 | { | |
1800 | int byte_misalign = LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo); | |
1801 | int elem_misalign = byte_misalign / element_size; | |
1802 | ||
1803 | if (vect_print_dump_info (REPORT_DETAILS)) | |
1804 | fprintf (vect_dump, "known alignment = %d.", byte_misalign); | |
1805 | ||
1806 | iters = build_int_cst (niters_type, | |
1807 | (((nelements - elem_misalign) & (nelements - 1)) / step)); | |
1808 | } | |
1809 | else | |
1810 | { | |
1811 | gimple_seq new_stmts = NULL; | |
1812 | tree start_addr = vect_create_addr_base_for_vector_ref (dr_stmt, | |
1813 | &new_stmts, NULL_TREE, loop); | |
1814 | tree ptr_type = TREE_TYPE (start_addr); | |
1815 | tree size = TYPE_SIZE (ptr_type); | |
1816 | tree type = lang_hooks.types.type_for_size (tree_low_cst (size, 1), 1); | |
1817 | tree vectype_size_minus_1 = build_int_cst (type, vectype_align - 1); | |
1818 | tree elem_size_log = | |
1819 | build_int_cst (type, exact_log2 (vectype_align/nelements)); | |
1820 | tree nelements_minus_1 = build_int_cst (type, nelements - 1); | |
1821 | tree nelements_tree = build_int_cst (type, nelements); | |
1822 | tree byte_misalign; | |
1823 | tree elem_misalign; | |
1824 | ||
1825 | new_bb = gsi_insert_seq_on_edge_immediate (pe, new_stmts); | |
1826 | gcc_assert (!new_bb); | |
1827 | ||
1828 | /* Create: byte_misalign = addr & (vectype_size - 1) */ | |
1829 | byte_misalign = | |
1830 | fold_build2 (BIT_AND_EXPR, type, fold_convert (type, start_addr), vectype_size_minus_1); | |
1831 | ||
1832 | /* Create: elem_misalign = byte_misalign / element_size */ | |
1833 | elem_misalign = | |
1834 | fold_build2 (RSHIFT_EXPR, type, byte_misalign, elem_size_log); | |
1835 | ||
1836 | /* Create: (niters_type) (nelements - elem_misalign)&(nelements - 1) */ | |
1837 | iters = fold_build2 (MINUS_EXPR, type, nelements_tree, elem_misalign); | |
1838 | iters = fold_build2 (BIT_AND_EXPR, type, iters, nelements_minus_1); | |
1839 | iters = fold_convert (niters_type, iters); | |
1840 | } | |
1841 | ||
1842 | /* Create: prolog_loop_niters = min (iters, loop_niters) */ | |
1843 | /* If the loop bound is known at compile time we already verified that it is | |
1844 | greater than vf; since the misalignment ('iters') is at most vf, there's | |
1845 | no need to generate the MIN_EXPR in this case. */ | |
1846 | if (TREE_CODE (loop_niters) != INTEGER_CST) | |
1847 | iters = fold_build2 (MIN_EXPR, niters_type, iters, loop_niters); | |
1848 | ||
1849 | if (vect_print_dump_info (REPORT_DETAILS)) | |
1850 | { | |
1851 | fprintf (vect_dump, "niters for prolog loop: "); | |
1852 | print_generic_expr (vect_dump, iters, TDF_SLIM); | |
1853 | } | |
1854 | ||
1855 | var = create_tmp_var (niters_type, "prolog_loop_niters"); | |
1856 | add_referenced_var (var); | |
1857 | stmts = NULL; | |
1858 | iters_name = force_gimple_operand (iters, &stmts, false, var); | |
1859 | ||
1860 | /* Insert stmt on loop preheader edge. */ | |
1861 | if (stmts) | |
1862 | { | |
1863 | basic_block new_bb = gsi_insert_seq_on_edge_immediate (pe, stmts); | |
1864 | gcc_assert (!new_bb); | |
1865 | } | |
1866 | ||
1867 | return iters_name; | |
1868 | } | |
1869 | ||
1870 | ||
1871 | /* Function vect_update_init_of_dr | |
1872 | ||
1873 | NITERS iterations were peeled from LOOP. DR represents a data reference | |
1874 | in LOOP. This function updates the information recorded in DR to | |
1875 | account for the fact that the first NITERS iterations had already been | |
1876 | executed. Specifically, it updates the OFFSET field of DR. */ | |
1877 | ||
1878 | static void | |
1879 | vect_update_init_of_dr (struct data_reference *dr, tree niters) | |
1880 | { | |
1881 | tree offset = DR_OFFSET (dr); | |
1882 | ||
1883 | niters = fold_build2 (MULT_EXPR, sizetype, | |
1884 | fold_convert (sizetype, niters), | |
1885 | fold_convert (sizetype, DR_STEP (dr))); | |
1886 | offset = fold_build2 (PLUS_EXPR, sizetype, offset, niters); | |
1887 | DR_OFFSET (dr) = offset; | |
1888 | } | |
1889 | ||
1890 | ||
1891 | /* Function vect_update_inits_of_drs | |
1892 | ||
1893 | NITERS iterations were peeled from the loop represented by LOOP_VINFO. | |
1894 | This function updates the information recorded for the data references in | |
1895 | the loop to account for the fact that the first NITERS iterations had | |
1896 | already been executed. Specifically, it updates the initial_condition of | |
1897 | the access_function of all the data_references in the loop. */ | |
1898 | ||
1899 | static void | |
1900 | vect_update_inits_of_drs (loop_vec_info loop_vinfo, tree niters) | |
1901 | { | |
1902 | unsigned int i; | |
1903 | VEC (data_reference_p, heap) *datarefs = LOOP_VINFO_DATAREFS (loop_vinfo); | |
1904 | struct data_reference *dr; | |
1905 | ||
1906 | if (vect_print_dump_info (REPORT_DETAILS)) | |
1907 | fprintf (vect_dump, "=== vect_update_inits_of_dr ==="); | |
1908 | ||
1909 | for (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++) | |
1910 | vect_update_init_of_dr (dr, niters); | |
1911 | } | |
1912 | ||
1913 | ||
1914 | /* Function vect_do_peeling_for_alignment | |
1915 | ||
1916 | Peel the first 'niters' iterations of the loop represented by LOOP_VINFO. | |
1917 | 'niters' is set to the misalignment of one of the data references in the | |
1918 | loop, thereby forcing it to refer to an aligned location at the beginning | |
1919 | of the execution of this loop. The data reference for which we are | |
1920 | peeling is recorded in LOOP_VINFO_UNALIGNED_DR. */ | |
1921 | ||
1922 | void | |
1923 | vect_do_peeling_for_alignment (loop_vec_info loop_vinfo) | |
1924 | { | |
1925 | struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); | |
1926 | tree niters_of_prolog_loop, ni_name; | |
1927 | tree n_iters; | |
1928 | struct loop *new_loop; | |
1929 | bool check_profitability = false; | |
1930 | unsigned int th = 0; | |
1931 | int min_profitable_iters; | |
1932 | ||
1933 | if (vect_print_dump_info (REPORT_DETAILS)) | |
1934 | fprintf (vect_dump, "=== vect_do_peeling_for_alignment ==="); | |
1935 | ||
1936 | initialize_original_copy_tables (); | |
1937 | ||
1938 | ni_name = vect_build_loop_niters (loop_vinfo); | |
1939 | niters_of_prolog_loop = vect_gen_niters_for_prolog_loop (loop_vinfo, ni_name); | |
1940 | ||
1941 | ||
1942 | /* If cost model check not done during versioning. */ | |
1943 | if (!VEC_length (gimple, LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo)) | |
1944 | && !VEC_length (ddr_p, LOOP_VINFO_MAY_ALIAS_DDRS (loop_vinfo))) | |
1945 | { | |
1946 | check_profitability = true; | |
1947 | ||
1948 | /* Get profitability threshold for vectorized loop. */ | |
1949 | min_profitable_iters = LOOP_VINFO_COST_MODEL_MIN_ITERS (loop_vinfo); | |
1950 | ||
1951 | th = conservative_cost_threshold (loop_vinfo, | |
1952 | min_profitable_iters); | |
1953 | } | |
1954 | ||
1955 | /* Peel the prolog loop and iterate it niters_of_prolog_loop. */ | |
1956 | new_loop = | |
1957 | slpeel_tree_peel_loop_to_edge (loop, loop_preheader_edge (loop), | |
1958 | niters_of_prolog_loop, ni_name, true, | |
1959 | th, check_profitability); | |
1960 | ||
1961 | gcc_assert (new_loop); | |
1962 | #ifdef ENABLE_CHECKING | |
1963 | slpeel_verify_cfg_after_peeling (new_loop, loop); | |
1964 | #endif | |
1965 | ||
1966 | /* Update number of times loop executes. */ | |
1967 | n_iters = LOOP_VINFO_NITERS (loop_vinfo); | |
1968 | LOOP_VINFO_NITERS (loop_vinfo) = fold_build2 (MINUS_EXPR, | |
1969 | TREE_TYPE (n_iters), n_iters, niters_of_prolog_loop); | |
1970 | ||
1971 | /* Update the init conditions of the access functions of all data refs. */ | |
1972 | vect_update_inits_of_drs (loop_vinfo, niters_of_prolog_loop); | |
1973 | ||
1974 | /* After peeling we have to reset scalar evolution analyzer. */ | |
1975 | scev_reset (); | |
1976 | ||
1977 | free_original_copy_tables (); | |
1978 | } | |
1979 | ||
1980 | ||
1981 | /* Function vect_create_cond_for_align_checks. | |
1982 | ||
1983 | Create a conditional expression that represents the alignment checks for | |
1984 | all of data references (array element references) whose alignment must be | |
1985 | checked at runtime. | |
1986 | ||
1987 | Input: | |
1988 | COND_EXPR - input conditional expression. New conditions will be chained | |
1989 | with logical AND operation. | |
1990 | LOOP_VINFO - two fields of the loop information are used. | |
1991 | LOOP_VINFO_PTR_MASK is the mask used to check the alignment. | |
1992 | LOOP_VINFO_MAY_MISALIGN_STMTS contains the refs to be checked. | |
1993 | ||
1994 | Output: | |
1995 | COND_EXPR_STMT_LIST - statements needed to construct the conditional | |
1996 | expression. | |
1997 | The returned value is the conditional expression to be used in the if | |
1998 | statement that controls which version of the loop gets executed at runtime. | |
1999 | ||
2000 | The algorithm makes two assumptions: | |
2001 | 1) The number of bytes "n" in a vector is a power of 2. | |
2002 | 2) An address "a" is aligned if a%n is zero and that this | |
2003 | test can be done as a&(n-1) == 0. For example, for 16 | |
2004 | byte vectors the test is a&0xf == 0. */ | |
2005 | ||
2006 | static void | |
2007 | vect_create_cond_for_align_checks (loop_vec_info loop_vinfo, | |
2008 | tree *cond_expr, | |
2009 | gimple_seq *cond_expr_stmt_list) | |
2010 | { | |
2011 | struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); | |
2012 | VEC(gimple,heap) *may_misalign_stmts | |
2013 | = LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo); | |
2014 | gimple ref_stmt; | |
2015 | int mask = LOOP_VINFO_PTR_MASK (loop_vinfo); | |
2016 | tree mask_cst; | |
2017 | unsigned int i; | |
2018 | tree psize; | |
2019 | tree int_ptrsize_type; | |
2020 | char tmp_name[20]; | |
2021 | tree or_tmp_name = NULL_TREE; | |
2022 | tree and_tmp, and_tmp_name; | |
2023 | gimple and_stmt; | |
2024 | tree ptrsize_zero; | |
2025 | tree part_cond_expr; | |
2026 | ||
2027 | /* Check that mask is one less than a power of 2, i.e., mask is | |
2028 | all zeros followed by all ones. */ | |
2029 | gcc_assert ((mask != 0) && ((mask & (mask+1)) == 0)); | |
2030 | ||
2031 | /* CHECKME: what is the best integer or unsigned type to use to hold a | |
2032 | cast from a pointer value? */ | |
2033 | psize = TYPE_SIZE (ptr_type_node); | |
2034 | int_ptrsize_type | |
2035 | = lang_hooks.types.type_for_size (tree_low_cst (psize, 1), 0); | |
2036 | ||
2037 | /* Create expression (mask & (dr_1 || ... || dr_n)) where dr_i is the address | |
2038 | of the first vector of the i'th data reference. */ | |
2039 | ||
2040 | for (i = 0; VEC_iterate (gimple, may_misalign_stmts, i, ref_stmt); i++) | |
2041 | { | |
2042 | gimple_seq new_stmt_list = NULL; | |
2043 | tree addr_base; | |
2044 | tree addr_tmp, addr_tmp_name; | |
2045 | tree or_tmp, new_or_tmp_name; | |
2046 | gimple addr_stmt, or_stmt; | |
2047 | ||
2048 | /* create: addr_tmp = (int)(address_of_first_vector) */ | |
2049 | addr_base = | |
2050 | vect_create_addr_base_for_vector_ref (ref_stmt, &new_stmt_list, | |
2051 | NULL_TREE, loop); | |
2052 | if (new_stmt_list != NULL) | |
2053 | gimple_seq_add_seq (cond_expr_stmt_list, new_stmt_list); | |
2054 | ||
2055 | sprintf (tmp_name, "%s%d", "addr2int", i); | |
2056 | addr_tmp = create_tmp_var (int_ptrsize_type, tmp_name); | |
2057 | add_referenced_var (addr_tmp); | |
2058 | addr_tmp_name = make_ssa_name (addr_tmp, NULL); | |
2059 | addr_stmt = gimple_build_assign_with_ops (NOP_EXPR, addr_tmp_name, | |
2060 | addr_base, NULL_TREE); | |
2061 | SSA_NAME_DEF_STMT (addr_tmp_name) = addr_stmt; | |
2062 | gimple_seq_add_stmt (cond_expr_stmt_list, addr_stmt); | |
2063 | ||
2064 | /* The addresses are OR together. */ | |
2065 | ||
2066 | if (or_tmp_name != NULL_TREE) | |
2067 | { | |
2068 | /* create: or_tmp = or_tmp | addr_tmp */ | |
2069 | sprintf (tmp_name, "%s%d", "orptrs", i); | |
2070 | or_tmp = create_tmp_var (int_ptrsize_type, tmp_name); | |
2071 | add_referenced_var (or_tmp); | |
2072 | new_or_tmp_name = make_ssa_name (or_tmp, NULL); | |
2073 | or_stmt = gimple_build_assign_with_ops (BIT_IOR_EXPR, | |
2074 | new_or_tmp_name, | |
2075 | or_tmp_name, addr_tmp_name); | |
2076 | SSA_NAME_DEF_STMT (new_or_tmp_name) = or_stmt; | |
2077 | gimple_seq_add_stmt (cond_expr_stmt_list, or_stmt); | |
2078 | or_tmp_name = new_or_tmp_name; | |
2079 | } | |
2080 | else | |
2081 | or_tmp_name = addr_tmp_name; | |
2082 | ||
2083 | } /* end for i */ | |
2084 | ||
2085 | mask_cst = build_int_cst (int_ptrsize_type, mask); | |
2086 | ||
2087 | /* create: and_tmp = or_tmp & mask */ | |
2088 | and_tmp = create_tmp_var (int_ptrsize_type, "andmask" ); | |
2089 | add_referenced_var (and_tmp); | |
2090 | and_tmp_name = make_ssa_name (and_tmp, NULL); | |
2091 | ||
2092 | and_stmt = gimple_build_assign_with_ops (BIT_AND_EXPR, and_tmp_name, | |
2093 | or_tmp_name, mask_cst); | |
2094 | SSA_NAME_DEF_STMT (and_tmp_name) = and_stmt; | |
2095 | gimple_seq_add_stmt (cond_expr_stmt_list, and_stmt); | |
2096 | ||
2097 | /* Make and_tmp the left operand of the conditional test against zero. | |
2098 | if and_tmp has a nonzero bit then some address is unaligned. */ | |
2099 | ptrsize_zero = build_int_cst (int_ptrsize_type, 0); | |
2100 | part_cond_expr = fold_build2 (EQ_EXPR, boolean_type_node, | |
2101 | and_tmp_name, ptrsize_zero); | |
2102 | if (*cond_expr) | |
2103 | *cond_expr = fold_build2 (TRUTH_AND_EXPR, boolean_type_node, | |
2104 | *cond_expr, part_cond_expr); | |
2105 | else | |
2106 | *cond_expr = part_cond_expr; | |
2107 | } | |
2108 | ||
2109 | ||
2110 | /* Function vect_vfa_segment_size. | |
2111 | ||
2112 | Create an expression that computes the size of segment | |
2113 | that will be accessed for a data reference. The functions takes into | |
2114 | account that realignment loads may access one more vector. | |
2115 | ||
2116 | Input: | |
2117 | DR: The data reference. | |
2118 | VECT_FACTOR: vectorization factor. | |
2119 | ||
2120 | Return an expression whose value is the size of segment which will be | |
2121 | accessed by DR. */ | |
2122 | ||
2123 | static tree | |
2124 | vect_vfa_segment_size (struct data_reference *dr, tree vect_factor) | |
2125 | { | |
2126 | tree segment_length = fold_build2 (MULT_EXPR, integer_type_node, | |
2127 | DR_STEP (dr), vect_factor); | |
2128 | ||
2129 | if (vect_supportable_dr_alignment (dr) == dr_explicit_realign_optimized) | |
2130 | { | |
2131 | tree vector_size = TYPE_SIZE_UNIT | |
2132 | (STMT_VINFO_VECTYPE (vinfo_for_stmt (DR_STMT (dr)))); | |
2133 | ||
2134 | segment_length = fold_build2 (PLUS_EXPR, integer_type_node, | |
2135 | segment_length, vector_size); | |
2136 | } | |
2137 | return fold_convert (sizetype, segment_length); | |
2138 | } | |
2139 | ||
2140 | ||
2141 | /* Function vect_create_cond_for_alias_checks. | |
2142 | ||
2143 | Create a conditional expression that represents the run-time checks for | |
2144 | overlapping of address ranges represented by a list of data references | |
2145 | relations passed as input. | |
2146 | ||
2147 | Input: | |
2148 | COND_EXPR - input conditional expression. New conditions will be chained | |
2149 | with logical AND operation. | |
2150 | LOOP_VINFO - field LOOP_VINFO_MAY_ALIAS_STMTS contains the list of ddrs | |
2151 | to be checked. | |
2152 | ||
2153 | Output: | |
2154 | COND_EXPR - conditional expression. | |
2155 | COND_EXPR_STMT_LIST - statements needed to construct the conditional | |
2156 | expression. | |
2157 | ||
2158 | ||
2159 | The returned value is the conditional expression to be used in the if | |
2160 | statement that controls which version of the loop gets executed at runtime. | |
2161 | */ | |
2162 | ||
2163 | static void | |
2164 | vect_create_cond_for_alias_checks (loop_vec_info loop_vinfo, | |
2165 | tree * cond_expr, | |
2166 | gimple_seq * cond_expr_stmt_list) | |
2167 | { | |
2168 | struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); | |
2169 | VEC (ddr_p, heap) * may_alias_ddrs = | |
2170 | LOOP_VINFO_MAY_ALIAS_DDRS (loop_vinfo); | |
2171 | tree vect_factor = | |
2172 | build_int_cst (integer_type_node, LOOP_VINFO_VECT_FACTOR (loop_vinfo)); | |
2173 | ||
2174 | ddr_p ddr; | |
2175 | unsigned int i; | |
2176 | tree part_cond_expr; | |
2177 | ||
2178 | /* Create expression | |
2179 | ((store_ptr_0 + store_segment_length_0) < load_ptr_0) | |
2180 | || (load_ptr_0 + load_segment_length_0) < store_ptr_0)) | |
2181 | && | |
2182 | ... | |
2183 | && | |
2184 | ((store_ptr_n + store_segment_length_n) < load_ptr_n) | |
2185 | || (load_ptr_n + load_segment_length_n) < store_ptr_n)) */ | |
2186 | ||
2187 | if (VEC_empty (ddr_p, may_alias_ddrs)) | |
2188 | return; | |
2189 | ||
2190 | for (i = 0; VEC_iterate (ddr_p, may_alias_ddrs, i, ddr); i++) | |
2191 | { | |
2192 | struct data_reference *dr_a, *dr_b; | |
2193 | gimple dr_group_first_a, dr_group_first_b; | |
2194 | tree addr_base_a, addr_base_b; | |
2195 | tree segment_length_a, segment_length_b; | |
2196 | gimple stmt_a, stmt_b; | |
2197 | ||
2198 | dr_a = DDR_A (ddr); | |
2199 | stmt_a = DR_STMT (DDR_A (ddr)); | |
2200 | dr_group_first_a = DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt_a)); | |
2201 | if (dr_group_first_a) | |
2202 | { | |
2203 | stmt_a = dr_group_first_a; | |
2204 | dr_a = STMT_VINFO_DATA_REF (vinfo_for_stmt (stmt_a)); | |
2205 | } | |
2206 | ||
2207 | dr_b = DDR_B (ddr); | |
2208 | stmt_b = DR_STMT (DDR_B (ddr)); | |
2209 | dr_group_first_b = DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt_b)); | |
2210 | if (dr_group_first_b) | |
2211 | { | |
2212 | stmt_b = dr_group_first_b; | |
2213 | dr_b = STMT_VINFO_DATA_REF (vinfo_for_stmt (stmt_b)); | |
2214 | } | |
2215 | ||
2216 | addr_base_a = | |
2217 | vect_create_addr_base_for_vector_ref (stmt_a, cond_expr_stmt_list, | |
2218 | NULL_TREE, loop); | |
2219 | addr_base_b = | |
2220 | vect_create_addr_base_for_vector_ref (stmt_b, cond_expr_stmt_list, | |
2221 | NULL_TREE, loop); | |
2222 | ||
2223 | segment_length_a = vect_vfa_segment_size (dr_a, vect_factor); | |
2224 | segment_length_b = vect_vfa_segment_size (dr_b, vect_factor); | |
2225 | ||
2226 | if (vect_print_dump_info (REPORT_DR_DETAILS)) | |
2227 | { | |
2228 | fprintf (vect_dump, | |
2229 | "create runtime check for data references "); | |
2230 | print_generic_expr (vect_dump, DR_REF (dr_a), TDF_SLIM); | |
2231 | fprintf (vect_dump, " and "); | |
2232 | print_generic_expr (vect_dump, DR_REF (dr_b), TDF_SLIM); | |
2233 | } | |
2234 | ||
2235 | ||
2236 | part_cond_expr = | |
2237 | fold_build2 (TRUTH_OR_EXPR, boolean_type_node, | |
2238 | fold_build2 (LT_EXPR, boolean_type_node, | |
2239 | fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (addr_base_a), | |
2240 | addr_base_a, | |
2241 | segment_length_a), | |
2242 | addr_base_b), | |
2243 | fold_build2 (LT_EXPR, boolean_type_node, | |
2244 | fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (addr_base_b), | |
2245 | addr_base_b, | |
2246 | segment_length_b), | |
2247 | addr_base_a)); | |
2248 | ||
2249 | if (*cond_expr) | |
2250 | *cond_expr = fold_build2 (TRUTH_AND_EXPR, boolean_type_node, | |
2251 | *cond_expr, part_cond_expr); | |
2252 | else | |
2253 | *cond_expr = part_cond_expr; | |
2254 | } | |
2255 | if (vect_print_dump_info (REPORT_VECTORIZED_LOOPS)) | |
2256 | fprintf (vect_dump, "created %u versioning for alias checks.\n", | |
2257 | VEC_length (ddr_p, may_alias_ddrs)); | |
2258 | ||
2259 | } | |
2260 | ||
2261 | ||
2262 | /* Function vect_loop_versioning. | |
2263 | ||
2264 | If the loop has data references that may or may not be aligned or/and | |
2265 | has data reference relations whose independence was not proven then | |
2266 | two versions of the loop need to be generated, one which is vectorized | |
2267 | and one which isn't. A test is then generated to control which of the | |
2268 | loops is executed. The test checks for the alignment of all of the | |
2269 | data references that may or may not be aligned. An additional | |
2270 | sequence of runtime tests is generated for each pairs of DDRs whose | |
2271 | independence was not proven. The vectorized version of loop is | |
2272 | executed only if both alias and alignment tests are passed. | |
2273 | ||
2274 | The test generated to check which version of loop is executed | |
2275 | is modified to also check for profitability as indicated by the | |
2276 | cost model initially. */ | |
2277 | ||
2278 | void | |
2279 | vect_loop_versioning (loop_vec_info loop_vinfo) | |
2280 | { | |
2281 | struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); | |
2282 | struct loop *nloop; | |
2283 | tree cond_expr = NULL_TREE; | |
2284 | gimple_seq cond_expr_stmt_list = NULL; | |
2285 | basic_block condition_bb; | |
2286 | gimple_stmt_iterator gsi, cond_exp_gsi; | |
2287 | basic_block merge_bb; | |
2288 | basic_block new_exit_bb; | |
2289 | edge new_exit_e, e; | |
2290 | gimple orig_phi, new_phi; | |
2291 | tree arg; | |
2292 | unsigned prob = 4 * REG_BR_PROB_BASE / 5; | |
2293 | gimple_seq gimplify_stmt_list = NULL; | |
2294 | tree scalar_loop_iters = LOOP_VINFO_NITERS (loop_vinfo); | |
2295 | int min_profitable_iters = 0; | |
2296 | unsigned int th; | |
2297 | ||
2298 | /* Get profitability threshold for vectorized loop. */ | |
2299 | min_profitable_iters = LOOP_VINFO_COST_MODEL_MIN_ITERS (loop_vinfo); | |
2300 | ||
2301 | th = conservative_cost_threshold (loop_vinfo, | |
2302 | min_profitable_iters); | |
2303 | ||
2304 | cond_expr = | |
2305 | fold_build2 (GT_EXPR, boolean_type_node, scalar_loop_iters, | |
2306 | build_int_cst (TREE_TYPE (scalar_loop_iters), th)); | |
2307 | ||
2308 | cond_expr = force_gimple_operand (cond_expr, &cond_expr_stmt_list, | |
2309 | false, NULL_TREE); | |
2310 | ||
2311 | if (VEC_length (gimple, LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo))) | |
2312 | vect_create_cond_for_align_checks (loop_vinfo, &cond_expr, | |
2313 | &cond_expr_stmt_list); | |
2314 | ||
2315 | if (VEC_length (ddr_p, LOOP_VINFO_MAY_ALIAS_DDRS (loop_vinfo))) | |
2316 | vect_create_cond_for_alias_checks (loop_vinfo, &cond_expr, | |
2317 | &cond_expr_stmt_list); | |
2318 | ||
2319 | cond_expr = | |
2320 | fold_build2 (NE_EXPR, boolean_type_node, cond_expr, integer_zero_node); | |
2321 | cond_expr = | |
2322 | force_gimple_operand (cond_expr, &gimplify_stmt_list, true, NULL_TREE); | |
2323 | gimple_seq_add_seq (&cond_expr_stmt_list, gimplify_stmt_list); | |
2324 | ||
2325 | initialize_original_copy_tables (); | |
2326 | nloop = loop_version (loop, cond_expr, &condition_bb, | |
2327 | prob, prob, REG_BR_PROB_BASE - prob, true); | |
2328 | free_original_copy_tables(); | |
2329 | ||
2330 | /* Loop versioning violates an assumption we try to maintain during | |
2331 | vectorization - that the loop exit block has a single predecessor. | |
2332 | After versioning, the exit block of both loop versions is the same | |
2333 | basic block (i.e. it has two predecessors). Just in order to simplify | |
2334 | following transformations in the vectorizer, we fix this situation | |
2335 | here by adding a new (empty) block on the exit-edge of the loop, | |
2336 | with the proper loop-exit phis to maintain loop-closed-form. */ | |
2337 | ||
2338 | merge_bb = single_exit (loop)->dest; | |
2339 | gcc_assert (EDGE_COUNT (merge_bb->preds) == 2); | |
2340 | new_exit_bb = split_edge (single_exit (loop)); | |
2341 | new_exit_e = single_exit (loop); | |
2342 | e = EDGE_SUCC (new_exit_bb, 0); | |
2343 | ||
2344 | for (gsi = gsi_start_phis (merge_bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
2345 | { | |
2346 | orig_phi = gsi_stmt (gsi); | |
2347 | new_phi = create_phi_node (SSA_NAME_VAR (PHI_RESULT (orig_phi)), | |
2348 | new_exit_bb); | |
2349 | arg = PHI_ARG_DEF_FROM_EDGE (orig_phi, e); | |
2350 | add_phi_arg (new_phi, arg, new_exit_e); | |
2351 | SET_PHI_ARG_DEF (orig_phi, e->dest_idx, PHI_RESULT (new_phi)); | |
2352 | } | |
2353 | ||
2354 | /* End loop-exit-fixes after versioning. */ | |
2355 | ||
2356 | update_ssa (TODO_update_ssa); | |
2357 | if (cond_expr_stmt_list) | |
2358 | { | |
2359 | cond_exp_gsi = gsi_last_bb (condition_bb); | |
2360 | gsi_insert_seq_before (&cond_exp_gsi, cond_expr_stmt_list, GSI_SAME_STMT); | |
2361 | } | |
2362 | } | |
2363 |