comparison gcc/tree-vect-data-refs.c @ 55:77e2b8dfacca gcc-4.4.5

update it from 4.4.3 to 4.5.0
author ryoma <e075725@ie.u-ryukyu.ac.jp>
date Fri, 12 Feb 2010 23:39:51 +0900
parents
children b7f97abdc517
comparison
equal deleted inserted replaced
52:c156f1bd5cd9 55:77e2b8dfacca
1 /* Data References Analysis and Manipulation Utilities for Vectorization.
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 "target.h"
30 #include "basic-block.h"
31 #include "diagnostic.h"
32 #include "tree-flow.h"
33 #include "tree-dump.h"
34 #include "cfgloop.h"
35 #include "expr.h"
36 #include "optabs.h"
37 #include "tree-chrec.h"
38 #include "tree-scalar-evolution.h"
39 #include "tree-vectorizer.h"
40 #include "toplev.h"
41
42
43 /* Return the smallest scalar part of STMT.
44 This is used to determine the vectype of the stmt. We generally set the
45 vectype according to the type of the result (lhs). For stmts whose
46 result-type is different than the type of the arguments (e.g., demotion,
47 promotion), vectype will be reset appropriately (later). Note that we have
48 to visit the smallest datatype in this function, because that determines the
49 VF. If the smallest datatype in the loop is present only as the rhs of a
50 promotion operation - we'd miss it.
51 Such a case, where a variable of this datatype does not appear in the lhs
52 anywhere in the loop, can only occur if it's an invariant: e.g.:
53 'int_x = (int) short_inv', which we'd expect to have been optimized away by
54 invariant motion. However, we cannot rely on invariant motion to always take
55 invariants out of the loop, and so in the case of promotion we also have to
56 check the rhs.
57 LHS_SIZE_UNIT and RHS_SIZE_UNIT contain the sizes of the corresponding
58 types. */
59
60 tree
61 vect_get_smallest_scalar_type (gimple stmt, HOST_WIDE_INT *lhs_size_unit,
62 HOST_WIDE_INT *rhs_size_unit)
63 {
64 tree scalar_type = gimple_expr_type (stmt);
65 HOST_WIDE_INT lhs, rhs;
66
67 lhs = rhs = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (scalar_type));
68
69 if (is_gimple_assign (stmt)
70 && (gimple_assign_cast_p (stmt)
71 || gimple_assign_rhs_code (stmt) == WIDEN_MULT_EXPR
72 || gimple_assign_rhs_code (stmt) == FLOAT_EXPR))
73 {
74 tree rhs_type = TREE_TYPE (gimple_assign_rhs1 (stmt));
75
76 rhs = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (rhs_type));
77 if (rhs < lhs)
78 scalar_type = rhs_type;
79 }
80
81 *lhs_size_unit = lhs;
82 *rhs_size_unit = rhs;
83 return scalar_type;
84 }
85
86
87 /* Find the place of the data-ref in STMT in the interleaving chain that starts
88 from FIRST_STMT. Return -1 if the data-ref is not a part of the chain. */
89
90 int
91 vect_get_place_in_interleaving_chain (gimple stmt, gimple first_stmt)
92 {
93 gimple next_stmt = first_stmt;
94 int result = 0;
95
96 if (first_stmt != DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt)))
97 return -1;
98
99 while (next_stmt && next_stmt != stmt)
100 {
101 result++;
102 next_stmt = DR_GROUP_NEXT_DR (vinfo_for_stmt (next_stmt));
103 }
104
105 if (next_stmt)
106 return result;
107 else
108 return -1;
109 }
110
111
112 /* Function vect_insert_into_interleaving_chain.
113
114 Insert DRA into the interleaving chain of DRB according to DRA's INIT. */
115
116 static void
117 vect_insert_into_interleaving_chain (struct data_reference *dra,
118 struct data_reference *drb)
119 {
120 gimple prev, next;
121 tree next_init;
122 stmt_vec_info stmtinfo_a = vinfo_for_stmt (DR_STMT (dra));
123 stmt_vec_info stmtinfo_b = vinfo_for_stmt (DR_STMT (drb));
124
125 prev = DR_GROUP_FIRST_DR (stmtinfo_b);
126 next = DR_GROUP_NEXT_DR (vinfo_for_stmt (prev));
127 while (next)
128 {
129 next_init = DR_INIT (STMT_VINFO_DATA_REF (vinfo_for_stmt (next)));
130 if (tree_int_cst_compare (next_init, DR_INIT (dra)) > 0)
131 {
132 /* Insert here. */
133 DR_GROUP_NEXT_DR (vinfo_for_stmt (prev)) = DR_STMT (dra);
134 DR_GROUP_NEXT_DR (stmtinfo_a) = next;
135 return;
136 }
137 prev = next;
138 next = DR_GROUP_NEXT_DR (vinfo_for_stmt (prev));
139 }
140
141 /* We got to the end of the list. Insert here. */
142 DR_GROUP_NEXT_DR (vinfo_for_stmt (prev)) = DR_STMT (dra);
143 DR_GROUP_NEXT_DR (stmtinfo_a) = NULL;
144 }
145
146
147 /* Function vect_update_interleaving_chain.
148
149 For two data-refs DRA and DRB that are a part of a chain interleaved data
150 accesses, update the interleaving chain. DRB's INIT is smaller than DRA's.
151
152 There are four possible cases:
153 1. New stmts - both DRA and DRB are not a part of any chain:
154 FIRST_DR = DRB
155 NEXT_DR (DRB) = DRA
156 2. DRB is a part of a chain and DRA is not:
157 no need to update FIRST_DR
158 no need to insert DRB
159 insert DRA according to init
160 3. DRA is a part of a chain and DRB is not:
161 if (init of FIRST_DR > init of DRB)
162 FIRST_DR = DRB
163 NEXT(FIRST_DR) = previous FIRST_DR
164 else
165 insert DRB according to its init
166 4. both DRA and DRB are in some interleaving chains:
167 choose the chain with the smallest init of FIRST_DR
168 insert the nodes of the second chain into the first one. */
169
170 static void
171 vect_update_interleaving_chain (struct data_reference *drb,
172 struct data_reference *dra)
173 {
174 stmt_vec_info stmtinfo_a = vinfo_for_stmt (DR_STMT (dra));
175 stmt_vec_info stmtinfo_b = vinfo_for_stmt (DR_STMT (drb));
176 tree next_init, init_dra_chain, init_drb_chain;
177 gimple first_a, first_b;
178 tree node_init;
179 gimple node, prev, next, first_stmt;
180
181 /* 1. New stmts - both DRA and DRB are not a part of any chain. */
182 if (!DR_GROUP_FIRST_DR (stmtinfo_a) && !DR_GROUP_FIRST_DR (stmtinfo_b))
183 {
184 DR_GROUP_FIRST_DR (stmtinfo_a) = DR_STMT (drb);
185 DR_GROUP_FIRST_DR (stmtinfo_b) = DR_STMT (drb);
186 DR_GROUP_NEXT_DR (stmtinfo_b) = DR_STMT (dra);
187 return;
188 }
189
190 /* 2. DRB is a part of a chain and DRA is not. */
191 if (!DR_GROUP_FIRST_DR (stmtinfo_a) && DR_GROUP_FIRST_DR (stmtinfo_b))
192 {
193 DR_GROUP_FIRST_DR (stmtinfo_a) = DR_GROUP_FIRST_DR (stmtinfo_b);
194 /* Insert DRA into the chain of DRB. */
195 vect_insert_into_interleaving_chain (dra, drb);
196 return;
197 }
198
199 /* 3. DRA is a part of a chain and DRB is not. */
200 if (DR_GROUP_FIRST_DR (stmtinfo_a) && !DR_GROUP_FIRST_DR (stmtinfo_b))
201 {
202 gimple old_first_stmt = DR_GROUP_FIRST_DR (stmtinfo_a);
203 tree init_old = DR_INIT (STMT_VINFO_DATA_REF (vinfo_for_stmt (
204 old_first_stmt)));
205 gimple tmp;
206
207 if (tree_int_cst_compare (init_old, DR_INIT (drb)) > 0)
208 {
209 /* DRB's init is smaller than the init of the stmt previously marked
210 as the first stmt of the interleaving chain of DRA. Therefore, we
211 update FIRST_STMT and put DRB in the head of the list. */
212 DR_GROUP_FIRST_DR (stmtinfo_b) = DR_STMT (drb);
213 DR_GROUP_NEXT_DR (stmtinfo_b) = old_first_stmt;
214
215 /* Update all the stmts in the list to point to the new FIRST_STMT. */
216 tmp = old_first_stmt;
217 while (tmp)
218 {
219 DR_GROUP_FIRST_DR (vinfo_for_stmt (tmp)) = DR_STMT (drb);
220 tmp = DR_GROUP_NEXT_DR (vinfo_for_stmt (tmp));
221 }
222 }
223 else
224 {
225 /* Insert DRB in the list of DRA. */
226 vect_insert_into_interleaving_chain (drb, dra);
227 DR_GROUP_FIRST_DR (stmtinfo_b) = DR_GROUP_FIRST_DR (stmtinfo_a);
228 }
229 return;
230 }
231
232 /* 4. both DRA and DRB are in some interleaving chains. */
233 first_a = DR_GROUP_FIRST_DR (stmtinfo_a);
234 first_b = DR_GROUP_FIRST_DR (stmtinfo_b);
235 if (first_a == first_b)
236 return;
237 init_dra_chain = DR_INIT (STMT_VINFO_DATA_REF (vinfo_for_stmt (first_a)));
238 init_drb_chain = DR_INIT (STMT_VINFO_DATA_REF (vinfo_for_stmt (first_b)));
239
240 if (tree_int_cst_compare (init_dra_chain, init_drb_chain) > 0)
241 {
242 /* Insert the nodes of DRA chain into the DRB chain.
243 After inserting a node, continue from this node of the DRB chain (don't
244 start from the beginning. */
245 node = DR_GROUP_FIRST_DR (stmtinfo_a);
246 prev = DR_GROUP_FIRST_DR (stmtinfo_b);
247 first_stmt = first_b;
248 }
249 else
250 {
251 /* Insert the nodes of DRB chain into the DRA chain.
252 After inserting a node, continue from this node of the DRA chain (don't
253 start from the beginning. */
254 node = DR_GROUP_FIRST_DR (stmtinfo_b);
255 prev = DR_GROUP_FIRST_DR (stmtinfo_a);
256 first_stmt = first_a;
257 }
258
259 while (node)
260 {
261 node_init = DR_INIT (STMT_VINFO_DATA_REF (vinfo_for_stmt (node)));
262 next = DR_GROUP_NEXT_DR (vinfo_for_stmt (prev));
263 while (next)
264 {
265 next_init = DR_INIT (STMT_VINFO_DATA_REF (vinfo_for_stmt (next)));
266 if (tree_int_cst_compare (next_init, node_init) > 0)
267 {
268 /* Insert here. */
269 DR_GROUP_NEXT_DR (vinfo_for_stmt (prev)) = node;
270 DR_GROUP_NEXT_DR (vinfo_for_stmt (node)) = next;
271 prev = node;
272 break;
273 }
274 prev = next;
275 next = DR_GROUP_NEXT_DR (vinfo_for_stmt (prev));
276 }
277 if (!next)
278 {
279 /* We got to the end of the list. Insert here. */
280 DR_GROUP_NEXT_DR (vinfo_for_stmt (prev)) = node;
281 DR_GROUP_NEXT_DR (vinfo_for_stmt (node)) = NULL;
282 prev = node;
283 }
284 DR_GROUP_FIRST_DR (vinfo_for_stmt (node)) = first_stmt;
285 node = DR_GROUP_NEXT_DR (vinfo_for_stmt (node));
286 }
287 }
288
289
290 /* Function vect_equal_offsets.
291
292 Check if OFFSET1 and OFFSET2 are identical expressions. */
293
294 static bool
295 vect_equal_offsets (tree offset1, tree offset2)
296 {
297 bool res0, res1;
298
299 STRIP_NOPS (offset1);
300 STRIP_NOPS (offset2);
301
302 if (offset1 == offset2)
303 return true;
304
305 if (TREE_CODE (offset1) != TREE_CODE (offset2)
306 || !BINARY_CLASS_P (offset1)
307 || !BINARY_CLASS_P (offset2))
308 return false;
309
310 res0 = vect_equal_offsets (TREE_OPERAND (offset1, 0),
311 TREE_OPERAND (offset2, 0));
312 res1 = vect_equal_offsets (TREE_OPERAND (offset1, 1),
313 TREE_OPERAND (offset2, 1));
314
315 return (res0 && res1);
316 }
317
318
319 /* Function vect_check_interleaving.
320
321 Check if DRA and DRB are a part of interleaving. In case they are, insert
322 DRA and DRB in an interleaving chain. */
323
324 static bool
325 vect_check_interleaving (struct data_reference *dra,
326 struct data_reference *drb)
327 {
328 HOST_WIDE_INT type_size_a, type_size_b, diff_mod_size, step, init_a, init_b;
329
330 /* Check that the data-refs have same first location (except init) and they
331 are both either store or load (not load and store). */
332 if ((DR_BASE_ADDRESS (dra) != DR_BASE_ADDRESS (drb)
333 && (TREE_CODE (DR_BASE_ADDRESS (dra)) != ADDR_EXPR
334 || TREE_CODE (DR_BASE_ADDRESS (drb)) != ADDR_EXPR
335 || TREE_OPERAND (DR_BASE_ADDRESS (dra), 0)
336 != TREE_OPERAND (DR_BASE_ADDRESS (drb),0)))
337 || !vect_equal_offsets (DR_OFFSET (dra), DR_OFFSET (drb))
338 || !tree_int_cst_compare (DR_INIT (dra), DR_INIT (drb))
339 || DR_IS_READ (dra) != DR_IS_READ (drb))
340 return false;
341
342 /* Check:
343 1. data-refs are of the same type
344 2. their steps are equal
345 3. the step (if greater than zero) is greater than the difference between
346 data-refs' inits. */
347 type_size_a = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (TREE_TYPE (DR_REF (dra))));
348 type_size_b = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (TREE_TYPE (DR_REF (drb))));
349
350 if (type_size_a != type_size_b
351 || tree_int_cst_compare (DR_STEP (dra), DR_STEP (drb))
352 || !types_compatible_p (TREE_TYPE (DR_REF (dra)),
353 TREE_TYPE (DR_REF (drb))))
354 return false;
355
356 init_a = TREE_INT_CST_LOW (DR_INIT (dra));
357 init_b = TREE_INT_CST_LOW (DR_INIT (drb));
358 step = TREE_INT_CST_LOW (DR_STEP (dra));
359
360 if (init_a > init_b)
361 {
362 /* If init_a == init_b + the size of the type * k, we have an interleaving,
363 and DRB is accessed before DRA. */
364 diff_mod_size = (init_a - init_b) % type_size_a;
365
366 if (step && (init_a - init_b) > step)
367 return false;
368
369 if (diff_mod_size == 0)
370 {
371 vect_update_interleaving_chain (drb, dra);
372 if (vect_print_dump_info (REPORT_DR_DETAILS))
373 {
374 fprintf (vect_dump, "Detected interleaving ");
375 print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM);
376 fprintf (vect_dump, " and ");
377 print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM);
378 }
379 return true;
380 }
381 }
382 else
383 {
384 /* If init_b == init_a + the size of the type * k, we have an
385 interleaving, and DRA is accessed before DRB. */
386 diff_mod_size = (init_b - init_a) % type_size_a;
387
388 if (step && (init_b - init_a) > step)
389 return false;
390
391 if (diff_mod_size == 0)
392 {
393 vect_update_interleaving_chain (dra, drb);
394 if (vect_print_dump_info (REPORT_DR_DETAILS))
395 {
396 fprintf (vect_dump, "Detected interleaving ");
397 print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM);
398 fprintf (vect_dump, " and ");
399 print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM);
400 }
401 return true;
402 }
403 }
404
405 return false;
406 }
407
408 /* Check if data references pointed by DR_I and DR_J are same or
409 belong to same interleaving group. Return FALSE if drs are
410 different, otherwise return TRUE. */
411
412 static bool
413 vect_same_range_drs (data_reference_p dr_i, data_reference_p dr_j)
414 {
415 gimple stmt_i = DR_STMT (dr_i);
416 gimple stmt_j = DR_STMT (dr_j);
417
418 if (operand_equal_p (DR_REF (dr_i), DR_REF (dr_j), 0)
419 || (DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt_i))
420 && DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt_j))
421 && (DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt_i))
422 == DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt_j)))))
423 return true;
424 else
425 return false;
426 }
427
428 /* If address ranges represented by DDR_I and DDR_J are equal,
429 return TRUE, otherwise return FALSE. */
430
431 static bool
432 vect_vfa_range_equal (ddr_p ddr_i, ddr_p ddr_j)
433 {
434 if ((vect_same_range_drs (DDR_A (ddr_i), DDR_A (ddr_j))
435 && vect_same_range_drs (DDR_B (ddr_i), DDR_B (ddr_j)))
436 || (vect_same_range_drs (DDR_A (ddr_i), DDR_B (ddr_j))
437 && vect_same_range_drs (DDR_B (ddr_i), DDR_A (ddr_j))))
438 return true;
439 else
440 return false;
441 }
442
443 /* Insert DDR into LOOP_VINFO list of ddrs that may alias and need to be
444 tested at run-time. Return TRUE if DDR was successfully inserted.
445 Return false if versioning is not supported. */
446
447 static bool
448 vect_mark_for_runtime_alias_test (ddr_p ddr, loop_vec_info loop_vinfo)
449 {
450 struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
451
452 if ((unsigned) PARAM_VALUE (PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS) == 0)
453 return false;
454
455 if (vect_print_dump_info (REPORT_DR_DETAILS))
456 {
457 fprintf (vect_dump, "mark for run-time aliasing test between ");
458 print_generic_expr (vect_dump, DR_REF (DDR_A (ddr)), TDF_SLIM);
459 fprintf (vect_dump, " and ");
460 print_generic_expr (vect_dump, DR_REF (DDR_B (ddr)), TDF_SLIM);
461 }
462
463 if (optimize_loop_nest_for_size_p (loop))
464 {
465 if (vect_print_dump_info (REPORT_DR_DETAILS))
466 fprintf (vect_dump, "versioning not supported when optimizing for size.");
467 return false;
468 }
469
470 /* FORNOW: We don't support versioning with outer-loop vectorization. */
471 if (loop->inner)
472 {
473 if (vect_print_dump_info (REPORT_DR_DETAILS))
474 fprintf (vect_dump, "versioning not yet supported for outer-loops.");
475 return false;
476 }
477
478 VEC_safe_push (ddr_p, heap, LOOP_VINFO_MAY_ALIAS_DDRS (loop_vinfo), ddr);
479 return true;
480 }
481
482
483 /* Function vect_analyze_data_ref_dependence.
484
485 Return TRUE if there (might) exist a dependence between a memory-reference
486 DRA and a memory-reference DRB. When versioning for alias may check a
487 dependence at run-time, return FALSE. */
488
489 static bool
490 vect_analyze_data_ref_dependence (struct data_dependence_relation *ddr,
491 loop_vec_info loop_vinfo)
492 {
493 unsigned int i;
494 struct loop *loop = NULL;
495 int vectorization_factor = 0;
496 struct data_reference *dra = DDR_A (ddr);
497 struct data_reference *drb = DDR_B (ddr);
498 stmt_vec_info stmtinfo_a = vinfo_for_stmt (DR_STMT (dra));
499 stmt_vec_info stmtinfo_b = vinfo_for_stmt (DR_STMT (drb));
500 int dra_size = GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dra))));
501 int drb_size = GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (drb))));
502 lambda_vector dist_v;
503 unsigned int loop_depth;
504
505 if (DDR_ARE_DEPENDENT (ddr) == chrec_known)
506 {
507 /* Independent data accesses. */
508 vect_check_interleaving (dra, drb);
509 return false;
510 }
511
512 if (loop_vinfo)
513 {
514 loop = LOOP_VINFO_LOOP (loop_vinfo);
515 vectorization_factor = LOOP_VINFO_VECT_FACTOR (loop_vinfo);
516 }
517
518 if ((DR_IS_READ (dra) && DR_IS_READ (drb) && loop_vinfo) || dra == drb)
519 return false;
520
521 if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know)
522 {
523 if (loop_vinfo)
524 {
525 if (vect_print_dump_info (REPORT_DR_DETAILS))
526 {
527 fprintf (vect_dump, "versioning for alias required: "
528 "can't determine dependence between ");
529 print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM);
530 fprintf (vect_dump, " and ");
531 print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM);
532 }
533
534 /* Add to list of ddrs that need to be tested at run-time. */
535 return !vect_mark_for_runtime_alias_test (ddr, loop_vinfo);
536 }
537
538 /* When vectorizing a basic block unknown depnedence can still mean
539 strided access. */
540 if (vect_check_interleaving (dra, drb))
541 return false;
542
543 if (vect_print_dump_info (REPORT_DR_DETAILS))
544 {
545 fprintf (vect_dump, "can't determine dependence between ");
546 print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM);
547 fprintf (vect_dump, " and ");
548 print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM);
549 }
550
551 return true;
552 }
553
554 /* Versioning for alias is not yet supported for basic block SLP, and
555 dependence distance is unapplicable, hence, in case of known data
556 dependence, basic block vectorization is impossible for now. */
557 if (!loop_vinfo)
558 {
559 if (dra != drb && vect_check_interleaving (dra, drb))
560 return false;
561
562 if (vect_print_dump_info (REPORT_DR_DETAILS))
563 {
564 fprintf (vect_dump, "determined dependence between ");
565 print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM);
566 fprintf (vect_dump, " and ");
567 print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM);
568 }
569
570 return true;
571 }
572
573 /* Loop-based vectorization and known data dependence. */
574 if (DDR_NUM_DIST_VECTS (ddr) == 0)
575 {
576 if (vect_print_dump_info (REPORT_DR_DETAILS))
577 {
578 fprintf (vect_dump, "versioning for alias required: bad dist vector for ");
579 print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM);
580 fprintf (vect_dump, " and ");
581 print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM);
582 }
583 /* Add to list of ddrs that need to be tested at run-time. */
584 return !vect_mark_for_runtime_alias_test (ddr, loop_vinfo);
585 }
586
587 loop_depth = index_in_loop_nest (loop->num, DDR_LOOP_NEST (ddr));
588 for (i = 0; VEC_iterate (lambda_vector, DDR_DIST_VECTS (ddr), i, dist_v); i++)
589 {
590 int dist = dist_v[loop_depth];
591
592 if (vect_print_dump_info (REPORT_DR_DETAILS))
593 fprintf (vect_dump, "dependence distance = %d.", dist);
594
595 /* Same loop iteration. */
596 if (dist % vectorization_factor == 0 && dra_size == drb_size)
597 {
598 /* Two references with distance zero have the same alignment. */
599 VEC_safe_push (dr_p, heap, STMT_VINFO_SAME_ALIGN_REFS (stmtinfo_a), drb);
600 VEC_safe_push (dr_p, heap, STMT_VINFO_SAME_ALIGN_REFS (stmtinfo_b), dra);
601 if (vect_print_dump_info (REPORT_ALIGNMENT))
602 fprintf (vect_dump, "accesses have the same alignment.");
603 if (vect_print_dump_info (REPORT_DR_DETAILS))
604 {
605 fprintf (vect_dump, "dependence distance modulo vf == 0 between ");
606 print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM);
607 fprintf (vect_dump, " and ");
608 print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM);
609 }
610
611 /* For interleaving, mark that there is a read-write dependency if
612 necessary. We check before that one of the data-refs is store. */
613 if (DR_IS_READ (dra))
614 DR_GROUP_READ_WRITE_DEPENDENCE (stmtinfo_a) = true;
615 else
616 {
617 if (DR_IS_READ (drb))
618 DR_GROUP_READ_WRITE_DEPENDENCE (stmtinfo_b) = true;
619 }
620
621 continue;
622 }
623
624 if (abs (dist) >= vectorization_factor
625 || (dist > 0 && DDR_REVERSED_P (ddr)))
626 {
627 /* Dependence distance does not create dependence, as far as
628 vectorization is concerned, in this case. If DDR_REVERSED_P the
629 order of the data-refs in DDR was reversed (to make distance
630 vector positive), and the actual distance is negative. */
631 if (vect_print_dump_info (REPORT_DR_DETAILS))
632 fprintf (vect_dump, "dependence distance >= VF or negative.");
633 continue;
634 }
635
636 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOCATIONS))
637 {
638 fprintf (vect_dump, "not vectorized, possible dependence "
639 "between data-refs ");
640 print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM);
641 fprintf (vect_dump, " and ");
642 print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM);
643 }
644
645 return true;
646 }
647
648 return false;
649 }
650
651 /* Function vect_analyze_data_ref_dependences.
652
653 Examine all the data references in the loop, and make sure there do not
654 exist any data dependences between them. */
655
656 bool
657 vect_analyze_data_ref_dependences (loop_vec_info loop_vinfo,
658 bb_vec_info bb_vinfo)
659 {
660 unsigned int i;
661 VEC (ddr_p, heap) *ddrs = NULL;
662 struct data_dependence_relation *ddr;
663
664 if (vect_print_dump_info (REPORT_DETAILS))
665 fprintf (vect_dump, "=== vect_analyze_dependences ===");
666
667 if (loop_vinfo)
668 ddrs = LOOP_VINFO_DDRS (loop_vinfo);
669 else
670 ddrs = BB_VINFO_DDRS (bb_vinfo);
671
672 for (i = 0; VEC_iterate (ddr_p, ddrs, i, ddr); i++)
673 if (vect_analyze_data_ref_dependence (ddr, loop_vinfo))
674 return false;
675
676 return true;
677 }
678
679
680 /* Function vect_compute_data_ref_alignment
681
682 Compute the misalignment of the data reference DR.
683
684 Output:
685 1. If during the misalignment computation it is found that the data reference
686 cannot be vectorized then false is returned.
687 2. DR_MISALIGNMENT (DR) is defined.
688
689 FOR NOW: No analysis is actually performed. Misalignment is calculated
690 only for trivial cases. TODO. */
691
692 static bool
693 vect_compute_data_ref_alignment (struct data_reference *dr)
694 {
695 gimple stmt = DR_STMT (dr);
696 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
697 loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info);
698 struct loop *loop = NULL;
699 tree ref = DR_REF (dr);
700 tree vectype;
701 tree base, base_addr;
702 bool base_aligned;
703 tree misalign;
704 tree aligned_to, alignment;
705
706 if (vect_print_dump_info (REPORT_DETAILS))
707 fprintf (vect_dump, "vect_compute_data_ref_alignment:");
708
709 if (loop_vinfo)
710 loop = LOOP_VINFO_LOOP (loop_vinfo);
711
712 /* Initialize misalignment to unknown. */
713 SET_DR_MISALIGNMENT (dr, -1);
714
715 misalign = DR_INIT (dr);
716 aligned_to = DR_ALIGNED_TO (dr);
717 base_addr = DR_BASE_ADDRESS (dr);
718 vectype = STMT_VINFO_VECTYPE (stmt_info);
719
720 /* In case the dataref is in an inner-loop of the loop that is being
721 vectorized (LOOP), we use the base and misalignment information
722 relative to the outer-loop (LOOP). This is ok only if the misalignment
723 stays the same throughout the execution of the inner-loop, which is why
724 we have to check that the stride of the dataref in the inner-loop evenly
725 divides by the vector size. */
726 if (loop && nested_in_vect_loop_p (loop, stmt))
727 {
728 tree step = DR_STEP (dr);
729 HOST_WIDE_INT dr_step = TREE_INT_CST_LOW (step);
730
731 if (dr_step % GET_MODE_SIZE (TYPE_MODE (vectype)) == 0)
732 {
733 if (vect_print_dump_info (REPORT_ALIGNMENT))
734 fprintf (vect_dump, "inner step divides the vector-size.");
735 misalign = STMT_VINFO_DR_INIT (stmt_info);
736 aligned_to = STMT_VINFO_DR_ALIGNED_TO (stmt_info);
737 base_addr = STMT_VINFO_DR_BASE_ADDRESS (stmt_info);
738 }
739 else
740 {
741 if (vect_print_dump_info (REPORT_ALIGNMENT))
742 fprintf (vect_dump, "inner step doesn't divide the vector-size.");
743 misalign = NULL_TREE;
744 }
745 }
746
747 base = build_fold_indirect_ref (base_addr);
748 alignment = ssize_int (TYPE_ALIGN (vectype)/BITS_PER_UNIT);
749
750 if ((aligned_to && tree_int_cst_compare (aligned_to, alignment) < 0)
751 || !misalign)
752 {
753 if (vect_print_dump_info (REPORT_ALIGNMENT))
754 {
755 fprintf (vect_dump, "Unknown alignment for access: ");
756 print_generic_expr (vect_dump, base, TDF_SLIM);
757 }
758 return true;
759 }
760
761 if ((DECL_P (base)
762 && tree_int_cst_compare (ssize_int (DECL_ALIGN_UNIT (base)),
763 alignment) >= 0)
764 || (TREE_CODE (base_addr) == SSA_NAME
765 && tree_int_cst_compare (ssize_int (TYPE_ALIGN_UNIT (TREE_TYPE (
766 TREE_TYPE (base_addr)))),
767 alignment) >= 0))
768 base_aligned = true;
769 else
770 base_aligned = false;
771
772 if (!base_aligned)
773 {
774 /* Do not change the alignment of global variables if
775 flag_section_anchors is enabled. */
776 if (!vect_can_force_dr_alignment_p (base, TYPE_ALIGN (vectype))
777 || (TREE_STATIC (base) && flag_section_anchors))
778 {
779 if (vect_print_dump_info (REPORT_DETAILS))
780 {
781 fprintf (vect_dump, "can't force alignment of ref: ");
782 print_generic_expr (vect_dump, ref, TDF_SLIM);
783 }
784 return true;
785 }
786
787 /* Force the alignment of the decl.
788 NOTE: This is the only change to the code we make during
789 the analysis phase, before deciding to vectorize the loop. */
790 if (vect_print_dump_info (REPORT_DETAILS))
791 fprintf (vect_dump, "force alignment");
792 DECL_ALIGN (base) = TYPE_ALIGN (vectype);
793 DECL_USER_ALIGN (base) = 1;
794 }
795
796 /* At this point we assume that the base is aligned. */
797 gcc_assert (base_aligned
798 || (TREE_CODE (base) == VAR_DECL
799 && DECL_ALIGN (base) >= TYPE_ALIGN (vectype)));
800
801 /* Modulo alignment. */
802 misalign = size_binop (FLOOR_MOD_EXPR, misalign, alignment);
803
804 if (!host_integerp (misalign, 1))
805 {
806 /* Negative or overflowed misalignment value. */
807 if (vect_print_dump_info (REPORT_DETAILS))
808 fprintf (vect_dump, "unexpected misalign value");
809 return false;
810 }
811
812 SET_DR_MISALIGNMENT (dr, TREE_INT_CST_LOW (misalign));
813
814 if (vect_print_dump_info (REPORT_DETAILS))
815 {
816 fprintf (vect_dump, "misalign = %d bytes of ref ", DR_MISALIGNMENT (dr));
817 print_generic_expr (vect_dump, ref, TDF_SLIM);
818 }
819
820 return true;
821 }
822
823
824 /* Function vect_compute_data_refs_alignment
825
826 Compute the misalignment of data references in the loop.
827 Return FALSE if a data reference is found that cannot be vectorized. */
828
829 static bool
830 vect_compute_data_refs_alignment (loop_vec_info loop_vinfo,
831 bb_vec_info bb_vinfo)
832 {
833 VEC (data_reference_p, heap) *datarefs;
834 struct data_reference *dr;
835 unsigned int i;
836
837 if (loop_vinfo)
838 datarefs = LOOP_VINFO_DATAREFS (loop_vinfo);
839 else
840 datarefs = BB_VINFO_DATAREFS (bb_vinfo);
841
842 for (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++)
843 if (!vect_compute_data_ref_alignment (dr))
844 return false;
845
846 return true;
847 }
848
849
850 /* Function vect_update_misalignment_for_peel
851
852 DR - the data reference whose misalignment is to be adjusted.
853 DR_PEEL - the data reference whose misalignment is being made
854 zero in the vector loop by the peel.
855 NPEEL - the number of iterations in the peel loop if the misalignment
856 of DR_PEEL is known at compile time. */
857
858 static void
859 vect_update_misalignment_for_peel (struct data_reference *dr,
860 struct data_reference *dr_peel, int npeel)
861 {
862 unsigned int i;
863 VEC(dr_p,heap) *same_align_drs;
864 struct data_reference *current_dr;
865 int dr_size = GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dr))));
866 int dr_peel_size = GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dr_peel))));
867 stmt_vec_info stmt_info = vinfo_for_stmt (DR_STMT (dr));
868 stmt_vec_info peel_stmt_info = vinfo_for_stmt (DR_STMT (dr_peel));
869
870 /* For interleaved data accesses the step in the loop must be multiplied by
871 the size of the interleaving group. */
872 if (STMT_VINFO_STRIDED_ACCESS (stmt_info))
873 dr_size *= DR_GROUP_SIZE (vinfo_for_stmt (DR_GROUP_FIRST_DR (stmt_info)));
874 if (STMT_VINFO_STRIDED_ACCESS (peel_stmt_info))
875 dr_peel_size *= DR_GROUP_SIZE (peel_stmt_info);
876
877 /* It can be assumed that the data refs with the same alignment as dr_peel
878 are aligned in the vector loop. */
879 same_align_drs
880 = STMT_VINFO_SAME_ALIGN_REFS (vinfo_for_stmt (DR_STMT (dr_peel)));
881 for (i = 0; VEC_iterate (dr_p, same_align_drs, i, current_dr); i++)
882 {
883 if (current_dr != dr)
884 continue;
885 gcc_assert (DR_MISALIGNMENT (dr) / dr_size ==
886 DR_MISALIGNMENT (dr_peel) / dr_peel_size);
887 SET_DR_MISALIGNMENT (dr, 0);
888 return;
889 }
890
891 if (known_alignment_for_access_p (dr)
892 && known_alignment_for_access_p (dr_peel))
893 {
894 int misal = DR_MISALIGNMENT (dr);
895 tree vectype = STMT_VINFO_VECTYPE (stmt_info);
896 misal += npeel * dr_size;
897 misal %= GET_MODE_SIZE (TYPE_MODE (vectype));
898 SET_DR_MISALIGNMENT (dr, misal);
899 return;
900 }
901
902 if (vect_print_dump_info (REPORT_DETAILS))
903 fprintf (vect_dump, "Setting misalignment to -1.");
904 SET_DR_MISALIGNMENT (dr, -1);
905 }
906
907
908 /* Function vect_verify_datarefs_alignment
909
910 Return TRUE if all data references in the loop can be
911 handled with respect to alignment. */
912
913 bool
914 vect_verify_datarefs_alignment (loop_vec_info loop_vinfo, bb_vec_info bb_vinfo)
915 {
916 VEC (data_reference_p, heap) *datarefs;
917 struct data_reference *dr;
918 enum dr_alignment_support supportable_dr_alignment;
919 unsigned int i;
920
921 if (loop_vinfo)
922 datarefs = LOOP_VINFO_DATAREFS (loop_vinfo);
923 else
924 datarefs = BB_VINFO_DATAREFS (bb_vinfo);
925
926 for (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++)
927 {
928 gimple stmt = DR_STMT (dr);
929 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
930
931 /* For interleaving, only the alignment of the first access matters. */
932 if (STMT_VINFO_STRIDED_ACCESS (stmt_info)
933 && DR_GROUP_FIRST_DR (stmt_info) != stmt)
934 continue;
935
936 supportable_dr_alignment = vect_supportable_dr_alignment (dr);
937 if (!supportable_dr_alignment)
938 {
939 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOCATIONS))
940 {
941 if (DR_IS_READ (dr))
942 fprintf (vect_dump,
943 "not vectorized: unsupported unaligned load.");
944 else
945 fprintf (vect_dump,
946 "not vectorized: unsupported unaligned store.");
947 }
948 return false;
949 }
950 if (supportable_dr_alignment != dr_aligned
951 && vect_print_dump_info (REPORT_ALIGNMENT))
952 fprintf (vect_dump, "Vectorizing an unaligned access.");
953 }
954 return true;
955 }
956
957
958 /* Function vector_alignment_reachable_p
959
960 Return true if vector alignment for DR is reachable by peeling
961 a few loop iterations. Return false otherwise. */
962
963 static bool
964 vector_alignment_reachable_p (struct data_reference *dr)
965 {
966 gimple stmt = DR_STMT (dr);
967 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
968 tree vectype = STMT_VINFO_VECTYPE (stmt_info);
969
970 if (STMT_VINFO_STRIDED_ACCESS (stmt_info))
971 {
972 /* For interleaved access we peel only if number of iterations in
973 the prolog loop ({VF - misalignment}), is a multiple of the
974 number of the interleaved accesses. */
975 int elem_size, mis_in_elements;
976 int nelements = TYPE_VECTOR_SUBPARTS (vectype);
977
978 /* FORNOW: handle only known alignment. */
979 if (!known_alignment_for_access_p (dr))
980 return false;
981
982 elem_size = GET_MODE_SIZE (TYPE_MODE (vectype)) / nelements;
983 mis_in_elements = DR_MISALIGNMENT (dr) / elem_size;
984
985 if ((nelements - mis_in_elements) % DR_GROUP_SIZE (stmt_info))
986 return false;
987 }
988
989 /* If misalignment is known at the compile time then allow peeling
990 only if natural alignment is reachable through peeling. */
991 if (known_alignment_for_access_p (dr) && !aligned_access_p (dr))
992 {
993 HOST_WIDE_INT elmsize =
994 int_cst_value (TYPE_SIZE_UNIT (TREE_TYPE (vectype)));
995 if (vect_print_dump_info (REPORT_DETAILS))
996 {
997 fprintf (vect_dump, "data size =" HOST_WIDE_INT_PRINT_DEC, elmsize);
998 fprintf (vect_dump, ". misalignment = %d. ", DR_MISALIGNMENT (dr));
999 }
1000 if (DR_MISALIGNMENT (dr) % elmsize)
1001 {
1002 if (vect_print_dump_info (REPORT_DETAILS))
1003 fprintf (vect_dump, "data size does not divide the misalignment.\n");
1004 return false;
1005 }
1006 }
1007
1008 if (!known_alignment_for_access_p (dr))
1009 {
1010 tree type = (TREE_TYPE (DR_REF (dr)));
1011 tree ba = DR_BASE_OBJECT (dr);
1012 bool is_packed = false;
1013
1014 if (ba)
1015 is_packed = contains_packed_reference (ba);
1016
1017 if (vect_print_dump_info (REPORT_DETAILS))
1018 fprintf (vect_dump, "Unknown misalignment, is_packed = %d",is_packed);
1019 if (targetm.vectorize.vector_alignment_reachable (type, is_packed))
1020 return true;
1021 else
1022 return false;
1023 }
1024
1025 return true;
1026 }
1027
1028 /* Function vect_enhance_data_refs_alignment
1029
1030 This pass will use loop versioning and loop peeling in order to enhance
1031 the alignment of data references in the loop.
1032
1033 FOR NOW: we assume that whatever versioning/peeling takes place, only the
1034 original loop is to be vectorized; Any other loops that are created by
1035 the transformations performed in this pass - are not supposed to be
1036 vectorized. This restriction will be relaxed.
1037
1038 This pass will require a cost model to guide it whether to apply peeling
1039 or versioning or a combination of the two. For example, the scheme that
1040 intel uses when given a loop with several memory accesses, is as follows:
1041 choose one memory access ('p') which alignment you want to force by doing
1042 peeling. Then, either (1) generate a loop in which 'p' is aligned and all
1043 other accesses are not necessarily aligned, or (2) use loop versioning to
1044 generate one loop in which all accesses are aligned, and another loop in
1045 which only 'p' is necessarily aligned.
1046
1047 ("Automatic Intra-Register Vectorization for the Intel Architecture",
1048 Aart J.C. Bik, Milind Girkar, Paul M. Grey and Ximmin Tian, International
1049 Journal of Parallel Programming, Vol. 30, No. 2, April 2002.)
1050
1051 Devising a cost model is the most critical aspect of this work. It will
1052 guide us on which access to peel for, whether to use loop versioning, how
1053 many versions to create, etc. The cost model will probably consist of
1054 generic considerations as well as target specific considerations (on
1055 powerpc for example, misaligned stores are more painful than misaligned
1056 loads).
1057
1058 Here are the general steps involved in alignment enhancements:
1059
1060 -- original loop, before alignment analysis:
1061 for (i=0; i<N; i++){
1062 x = q[i]; # DR_MISALIGNMENT(q) = unknown
1063 p[i] = y; # DR_MISALIGNMENT(p) = unknown
1064 }
1065
1066 -- After vect_compute_data_refs_alignment:
1067 for (i=0; i<N; i++){
1068 x = q[i]; # DR_MISALIGNMENT(q) = 3
1069 p[i] = y; # DR_MISALIGNMENT(p) = unknown
1070 }
1071
1072 -- Possibility 1: we do loop versioning:
1073 if (p is aligned) {
1074 for (i=0; i<N; i++){ # loop 1A
1075 x = q[i]; # DR_MISALIGNMENT(q) = 3
1076 p[i] = y; # DR_MISALIGNMENT(p) = 0
1077 }
1078 }
1079 else {
1080 for (i=0; i<N; i++){ # loop 1B
1081 x = q[i]; # DR_MISALIGNMENT(q) = 3
1082 p[i] = y; # DR_MISALIGNMENT(p) = unaligned
1083 }
1084 }
1085
1086 -- Possibility 2: we do loop peeling:
1087 for (i = 0; i < 3; i++){ # (scalar loop, not to be vectorized).
1088 x = q[i];
1089 p[i] = y;
1090 }
1091 for (i = 3; i < N; i++){ # loop 2A
1092 x = q[i]; # DR_MISALIGNMENT(q) = 0
1093 p[i] = y; # DR_MISALIGNMENT(p) = unknown
1094 }
1095
1096 -- Possibility 3: combination of loop peeling and versioning:
1097 for (i = 0; i < 3; i++){ # (scalar loop, not to be vectorized).
1098 x = q[i];
1099 p[i] = y;
1100 }
1101 if (p is aligned) {
1102 for (i = 3; i<N; i++){ # loop 3A
1103 x = q[i]; # DR_MISALIGNMENT(q) = 0
1104 p[i] = y; # DR_MISALIGNMENT(p) = 0
1105 }
1106 }
1107 else {
1108 for (i = 3; i<N; i++){ # loop 3B
1109 x = q[i]; # DR_MISALIGNMENT(q) = 0
1110 p[i] = y; # DR_MISALIGNMENT(p) = unaligned
1111 }
1112 }
1113
1114 These loops are later passed to loop_transform to be vectorized. The
1115 vectorizer will use the alignment information to guide the transformation
1116 (whether to generate regular loads/stores, or with special handling for
1117 misalignment). */
1118
1119 bool
1120 vect_enhance_data_refs_alignment (loop_vec_info loop_vinfo)
1121 {
1122 VEC (data_reference_p, heap) *datarefs = LOOP_VINFO_DATAREFS (loop_vinfo);
1123 struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
1124 enum dr_alignment_support supportable_dr_alignment;
1125 struct data_reference *dr0 = NULL;
1126 struct data_reference *dr;
1127 unsigned int i;
1128 bool do_peeling = false;
1129 bool do_versioning = false;
1130 bool stat;
1131 gimple stmt;
1132 stmt_vec_info stmt_info;
1133 int vect_versioning_for_alias_required;
1134
1135 if (vect_print_dump_info (REPORT_DETAILS))
1136 fprintf (vect_dump, "=== vect_enhance_data_refs_alignment ===");
1137
1138 /* While cost model enhancements are expected in the future, the high level
1139 view of the code at this time is as follows:
1140
1141 A) If there is a misaligned access then see if peeling to align
1142 this access can make all data references satisfy
1143 vect_supportable_dr_alignment. If so, update data structures
1144 as needed and return true.
1145
1146 B) If peeling wasn't possible and there is a data reference with an
1147 unknown misalignment that does not satisfy vect_supportable_dr_alignment
1148 then see if loop versioning checks can be used to make all data
1149 references satisfy vect_supportable_dr_alignment. If so, update
1150 data structures as needed and return true.
1151
1152 C) If neither peeling nor versioning were successful then return false if
1153 any data reference does not satisfy vect_supportable_dr_alignment.
1154
1155 D) Return true (all data references satisfy vect_supportable_dr_alignment).
1156
1157 Note, Possibility 3 above (which is peeling and versioning together) is not
1158 being done at this time. */
1159
1160 /* (1) Peeling to force alignment. */
1161
1162 /* (1.1) Decide whether to perform peeling, and how many iterations to peel:
1163 Considerations:
1164 + How many accesses will become aligned due to the peeling
1165 - How many accesses will become unaligned due to the peeling,
1166 and the cost of misaligned accesses.
1167 - The cost of peeling (the extra runtime checks, the increase
1168 in code size).
1169
1170 The scheme we use FORNOW: peel to force the alignment of the first
1171 unsupported misaligned access in the loop.
1172
1173 TODO: Use a cost model. */
1174
1175 for (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++)
1176 {
1177 stmt = DR_STMT (dr);
1178 stmt_info = vinfo_for_stmt (stmt);
1179
1180 /* For interleaving, only the alignment of the first access
1181 matters. */
1182 if (STMT_VINFO_STRIDED_ACCESS (stmt_info)
1183 && DR_GROUP_FIRST_DR (stmt_info) != stmt)
1184 continue;
1185
1186 if (!DR_IS_READ (dr) && !aligned_access_p (dr))
1187 {
1188 do_peeling = vector_alignment_reachable_p (dr);
1189 if (do_peeling)
1190 dr0 = dr;
1191 if (!do_peeling && vect_print_dump_info (REPORT_DETAILS))
1192 fprintf (vect_dump, "vector alignment may not be reachable");
1193 break;
1194 }
1195 }
1196
1197 vect_versioning_for_alias_required
1198 = LOOP_REQUIRES_VERSIONING_FOR_ALIAS (loop_vinfo);
1199
1200 /* Temporarily, if versioning for alias is required, we disable peeling
1201 until we support peeling and versioning. Often peeling for alignment
1202 will require peeling for loop-bound, which in turn requires that we
1203 know how to adjust the loop ivs after the loop. */
1204 if (vect_versioning_for_alias_required
1205 || !vect_can_advance_ivs_p (loop_vinfo)
1206 || !slpeel_can_duplicate_loop_p (loop, single_exit (loop)))
1207 do_peeling = false;
1208
1209 if (do_peeling)
1210 {
1211 int mis;
1212 int npeel = 0;
1213 gimple stmt = DR_STMT (dr0);
1214 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
1215 tree vectype = STMT_VINFO_VECTYPE (stmt_info);
1216 int nelements = TYPE_VECTOR_SUBPARTS (vectype);
1217
1218 if (known_alignment_for_access_p (dr0))
1219 {
1220 /* Since it's known at compile time, compute the number of iterations
1221 in the peeled loop (the peeling factor) for use in updating
1222 DR_MISALIGNMENT values. The peeling factor is the vectorization
1223 factor minus the misalignment as an element count. */
1224 mis = DR_MISALIGNMENT (dr0);
1225 mis /= GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dr0))));
1226 npeel = nelements - mis;
1227
1228 /* For interleaved data access every iteration accesses all the
1229 members of the group, therefore we divide the number of iterations
1230 by the group size. */
1231 stmt_info = vinfo_for_stmt (DR_STMT (dr0));
1232 if (STMT_VINFO_STRIDED_ACCESS (stmt_info))
1233 npeel /= DR_GROUP_SIZE (stmt_info);
1234
1235 if (vect_print_dump_info (REPORT_DETAILS))
1236 fprintf (vect_dump, "Try peeling by %d", npeel);
1237 }
1238
1239 /* Ensure that all data refs can be vectorized after the peel. */
1240 for (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++)
1241 {
1242 int save_misalignment;
1243
1244 if (dr == dr0)
1245 continue;
1246
1247 stmt = DR_STMT (dr);
1248 stmt_info = vinfo_for_stmt (stmt);
1249 /* For interleaving, only the alignment of the first access
1250 matters. */
1251 if (STMT_VINFO_STRIDED_ACCESS (stmt_info)
1252 && DR_GROUP_FIRST_DR (stmt_info) != stmt)
1253 continue;
1254
1255 save_misalignment = DR_MISALIGNMENT (dr);
1256 vect_update_misalignment_for_peel (dr, dr0, npeel);
1257 supportable_dr_alignment = vect_supportable_dr_alignment (dr);
1258 SET_DR_MISALIGNMENT (dr, save_misalignment);
1259
1260 if (!supportable_dr_alignment)
1261 {
1262 do_peeling = false;
1263 break;
1264 }
1265 }
1266
1267 if (do_peeling)
1268 {
1269 /* (1.2) Update the DR_MISALIGNMENT of each data reference DR_i.
1270 If the misalignment of DR_i is identical to that of dr0 then set
1271 DR_MISALIGNMENT (DR_i) to zero. If the misalignment of DR_i and
1272 dr0 are known at compile time then increment DR_MISALIGNMENT (DR_i)
1273 by the peeling factor times the element size of DR_i (MOD the
1274 vectorization factor times the size). Otherwise, the
1275 misalignment of DR_i must be set to unknown. */
1276 for (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++)
1277 if (dr != dr0)
1278 vect_update_misalignment_for_peel (dr, dr0, npeel);
1279
1280 LOOP_VINFO_UNALIGNED_DR (loop_vinfo) = dr0;
1281 LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo) = DR_MISALIGNMENT (dr0);
1282 SET_DR_MISALIGNMENT (dr0, 0);
1283 if (vect_print_dump_info (REPORT_ALIGNMENT))
1284 fprintf (vect_dump, "Alignment of access forced using peeling.");
1285
1286 if (vect_print_dump_info (REPORT_DETAILS))
1287 fprintf (vect_dump, "Peeling for alignment will be applied.");
1288
1289 stat = vect_verify_datarefs_alignment (loop_vinfo, NULL);
1290 gcc_assert (stat);
1291 return stat;
1292 }
1293 }
1294
1295
1296 /* (2) Versioning to force alignment. */
1297
1298 /* Try versioning if:
1299 1) flag_tree_vect_loop_version is TRUE
1300 2) optimize loop for speed
1301 3) there is at least one unsupported misaligned data ref with an unknown
1302 misalignment, and
1303 4) all misaligned data refs with a known misalignment are supported, and
1304 5) the number of runtime alignment checks is within reason. */
1305
1306 do_versioning =
1307 flag_tree_vect_loop_version
1308 && optimize_loop_nest_for_speed_p (loop)
1309 && (!loop->inner); /* FORNOW */
1310
1311 if (do_versioning)
1312 {
1313 for (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++)
1314 {
1315 stmt = DR_STMT (dr);
1316 stmt_info = vinfo_for_stmt (stmt);
1317
1318 /* For interleaving, only the alignment of the first access
1319 matters. */
1320 if (aligned_access_p (dr)
1321 || (STMT_VINFO_STRIDED_ACCESS (stmt_info)
1322 && DR_GROUP_FIRST_DR (stmt_info) != stmt))
1323 continue;
1324
1325 supportable_dr_alignment = vect_supportable_dr_alignment (dr);
1326
1327 if (!supportable_dr_alignment)
1328 {
1329 gimple stmt;
1330 int mask;
1331 tree vectype;
1332
1333 if (known_alignment_for_access_p (dr)
1334 || VEC_length (gimple,
1335 LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo))
1336 >= (unsigned) PARAM_VALUE (PARAM_VECT_MAX_VERSION_FOR_ALIGNMENT_CHECKS))
1337 {
1338 do_versioning = false;
1339 break;
1340 }
1341
1342 stmt = DR_STMT (dr);
1343 vectype = STMT_VINFO_VECTYPE (vinfo_for_stmt (stmt));
1344 gcc_assert (vectype);
1345
1346 /* The rightmost bits of an aligned address must be zeros.
1347 Construct the mask needed for this test. For example,
1348 GET_MODE_SIZE for the vector mode V4SI is 16 bytes so the
1349 mask must be 15 = 0xf. */
1350 mask = GET_MODE_SIZE (TYPE_MODE (vectype)) - 1;
1351
1352 /* FORNOW: use the same mask to test all potentially unaligned
1353 references in the loop. The vectorizer currently supports
1354 a single vector size, see the reference to
1355 GET_MODE_NUNITS (TYPE_MODE (vectype)) where the
1356 vectorization factor is computed. */
1357 gcc_assert (!LOOP_VINFO_PTR_MASK (loop_vinfo)
1358 || LOOP_VINFO_PTR_MASK (loop_vinfo) == mask);
1359 LOOP_VINFO_PTR_MASK (loop_vinfo) = mask;
1360 VEC_safe_push (gimple, heap,
1361 LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo),
1362 DR_STMT (dr));
1363 }
1364 }
1365
1366 /* Versioning requires at least one misaligned data reference. */
1367 if (!LOOP_REQUIRES_VERSIONING_FOR_ALIGNMENT (loop_vinfo))
1368 do_versioning = false;
1369 else if (!do_versioning)
1370 VEC_truncate (gimple, LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo), 0);
1371 }
1372
1373 if (do_versioning)
1374 {
1375 VEC(gimple,heap) *may_misalign_stmts
1376 = LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo);
1377 gimple stmt;
1378
1379 /* It can now be assumed that the data references in the statements
1380 in LOOP_VINFO_MAY_MISALIGN_STMTS will be aligned in the version
1381 of the loop being vectorized. */
1382 for (i = 0; VEC_iterate (gimple, may_misalign_stmts, i, stmt); i++)
1383 {
1384 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
1385 dr = STMT_VINFO_DATA_REF (stmt_info);
1386 SET_DR_MISALIGNMENT (dr, 0);
1387 if (vect_print_dump_info (REPORT_ALIGNMENT))
1388 fprintf (vect_dump, "Alignment of access forced using versioning.");
1389 }
1390
1391 if (vect_print_dump_info (REPORT_DETAILS))
1392 fprintf (vect_dump, "Versioning for alignment will be applied.");
1393
1394 /* Peeling and versioning can't be done together at this time. */
1395 gcc_assert (! (do_peeling && do_versioning));
1396
1397 stat = vect_verify_datarefs_alignment (loop_vinfo, NULL);
1398 gcc_assert (stat);
1399 return stat;
1400 }
1401
1402 /* This point is reached if neither peeling nor versioning is being done. */
1403 gcc_assert (! (do_peeling || do_versioning));
1404
1405 stat = vect_verify_datarefs_alignment (loop_vinfo, NULL);
1406 return stat;
1407 }
1408
1409
1410 /* Function vect_analyze_data_refs_alignment
1411
1412 Analyze the alignment of the data-references in the loop.
1413 Return FALSE if a data reference is found that cannot be vectorized. */
1414
1415 bool
1416 vect_analyze_data_refs_alignment (loop_vec_info loop_vinfo,
1417 bb_vec_info bb_vinfo)
1418 {
1419 if (vect_print_dump_info (REPORT_DETAILS))
1420 fprintf (vect_dump, "=== vect_analyze_data_refs_alignment ===");
1421
1422 if (!vect_compute_data_refs_alignment (loop_vinfo, bb_vinfo))
1423 {
1424 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOCATIONS))
1425 fprintf (vect_dump,
1426 "not vectorized: can't calculate alignment for data ref.");
1427 return false;
1428 }
1429
1430 return true;
1431 }
1432
1433
1434 /* Analyze groups of strided accesses: check that DR belongs to a group of
1435 strided accesses of legal size, step, etc. Detect gaps, single element
1436 interleaving, and other special cases. Set strided access info.
1437 Collect groups of strided stores for further use in SLP analysis. */
1438
1439 static bool
1440 vect_analyze_group_access (struct data_reference *dr)
1441 {
1442 tree step = DR_STEP (dr);
1443 tree scalar_type = TREE_TYPE (DR_REF (dr));
1444 HOST_WIDE_INT type_size = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (scalar_type));
1445 gimple stmt = DR_STMT (dr);
1446 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
1447 loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info);
1448 bb_vec_info bb_vinfo = STMT_VINFO_BB_VINFO (stmt_info);
1449 HOST_WIDE_INT dr_step = TREE_INT_CST_LOW (step);
1450 HOST_WIDE_INT stride;
1451 bool slp_impossible = false;
1452
1453 /* For interleaving, STRIDE is STEP counted in elements, i.e., the size of the
1454 interleaving group (including gaps). */
1455 stride = dr_step / type_size;
1456
1457 /* Not consecutive access is possible only if it is a part of interleaving. */
1458 if (!DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt)))
1459 {
1460 /* Check if it this DR is a part of interleaving, and is a single
1461 element of the group that is accessed in the loop. */
1462
1463 /* Gaps are supported only for loads. STEP must be a multiple of the type
1464 size. The size of the group must be a power of 2. */
1465 if (DR_IS_READ (dr)
1466 && (dr_step % type_size) == 0
1467 && stride > 0
1468 && exact_log2 (stride) != -1)
1469 {
1470 DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt)) = stmt;
1471 DR_GROUP_SIZE (vinfo_for_stmt (stmt)) = stride;
1472 if (vect_print_dump_info (REPORT_DR_DETAILS))
1473 {
1474 fprintf (vect_dump, "Detected single element interleaving ");
1475 print_generic_expr (vect_dump, DR_REF (dr), TDF_SLIM);
1476 fprintf (vect_dump, " step ");
1477 print_generic_expr (vect_dump, step, TDF_SLIM);
1478 }
1479 return true;
1480 }
1481 if (vect_print_dump_info (REPORT_DETAILS))
1482 fprintf (vect_dump, "not consecutive access");
1483 return false;
1484 }
1485
1486 if (DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt)) == stmt)
1487 {
1488 /* First stmt in the interleaving chain. Check the chain. */
1489 gimple next = DR_GROUP_NEXT_DR (vinfo_for_stmt (stmt));
1490 struct data_reference *data_ref = dr;
1491 unsigned int count = 1;
1492 tree next_step;
1493 tree prev_init = DR_INIT (data_ref);
1494 gimple prev = stmt;
1495 HOST_WIDE_INT diff, count_in_bytes, gaps = 0;
1496
1497 while (next)
1498 {
1499 /* Skip same data-refs. In case that two or more stmts share data-ref
1500 (supported only for loads), we vectorize only the first stmt, and
1501 the rest get their vectorized loads from the first one. */
1502 if (!tree_int_cst_compare (DR_INIT (data_ref),
1503 DR_INIT (STMT_VINFO_DATA_REF (
1504 vinfo_for_stmt (next)))))
1505 {
1506 if (!DR_IS_READ (data_ref))
1507 {
1508 if (vect_print_dump_info (REPORT_DETAILS))
1509 fprintf (vect_dump, "Two store stmts share the same dr.");
1510 return false;
1511 }
1512
1513 /* Check that there is no load-store dependencies for this loads
1514 to prevent a case of load-store-load to the same location. */
1515 if (DR_GROUP_READ_WRITE_DEPENDENCE (vinfo_for_stmt (next))
1516 || DR_GROUP_READ_WRITE_DEPENDENCE (vinfo_for_stmt (prev)))
1517 {
1518 if (vect_print_dump_info (REPORT_DETAILS))
1519 fprintf (vect_dump,
1520 "READ_WRITE dependence in interleaving.");
1521 return false;
1522 }
1523
1524 /* For load use the same data-ref load. */
1525 DR_GROUP_SAME_DR_STMT (vinfo_for_stmt (next)) = prev;
1526
1527 prev = next;
1528 next = DR_GROUP_NEXT_DR (vinfo_for_stmt (next));
1529 continue;
1530 }
1531 prev = next;
1532
1533 /* Check that all the accesses have the same STEP. */
1534 next_step = DR_STEP (STMT_VINFO_DATA_REF (vinfo_for_stmt (next)));
1535 if (tree_int_cst_compare (step, next_step))
1536 {
1537 if (vect_print_dump_info (REPORT_DETAILS))
1538 fprintf (vect_dump, "not consecutive access in interleaving");
1539 return false;
1540 }
1541
1542 data_ref = STMT_VINFO_DATA_REF (vinfo_for_stmt (next));
1543 /* Check that the distance between two accesses is equal to the type
1544 size. Otherwise, we have gaps. */
1545 diff = (TREE_INT_CST_LOW (DR_INIT (data_ref))
1546 - TREE_INT_CST_LOW (prev_init)) / type_size;
1547 if (diff != 1)
1548 {
1549 /* FORNOW: SLP of accesses with gaps is not supported. */
1550 slp_impossible = true;
1551 if (!DR_IS_READ (data_ref))
1552 {
1553 if (vect_print_dump_info (REPORT_DETAILS))
1554 fprintf (vect_dump, "interleaved store with gaps");
1555 return false;
1556 }
1557
1558 gaps += diff - 1;
1559 }
1560
1561 /* Store the gap from the previous member of the group. If there is no
1562 gap in the access, DR_GROUP_GAP is always 1. */
1563 DR_GROUP_GAP (vinfo_for_stmt (next)) = diff;
1564
1565 prev_init = DR_INIT (data_ref);
1566 next = DR_GROUP_NEXT_DR (vinfo_for_stmt (next));
1567 /* Count the number of data-refs in the chain. */
1568 count++;
1569 }
1570
1571 /* COUNT is the number of accesses found, we multiply it by the size of
1572 the type to get COUNT_IN_BYTES. */
1573 count_in_bytes = type_size * count;
1574
1575 /* Check that the size of the interleaving (including gaps) is not
1576 greater than STEP. */
1577 if (dr_step && dr_step < count_in_bytes + gaps * type_size)
1578 {
1579 if (vect_print_dump_info (REPORT_DETAILS))
1580 {
1581 fprintf (vect_dump, "interleaving size is greater than step for ");
1582 print_generic_expr (vect_dump, DR_REF (dr), TDF_SLIM);
1583 }
1584 return false;
1585 }
1586
1587 /* Check that the size of the interleaving is equal to STEP for stores,
1588 i.e., that there are no gaps. */
1589 if (dr_step && dr_step != count_in_bytes)
1590 {
1591 if (DR_IS_READ (dr))
1592 {
1593 slp_impossible = true;
1594 /* There is a gap after the last load in the group. This gap is a
1595 difference between the stride and the number of elements. When
1596 there is no gap, this difference should be 0. */
1597 DR_GROUP_GAP (vinfo_for_stmt (stmt)) = stride - count;
1598 }
1599 else
1600 {
1601 if (vect_print_dump_info (REPORT_DETAILS))
1602 fprintf (vect_dump, "interleaved store with gaps");
1603 return false;
1604 }
1605 }
1606
1607 /* Check that STEP is a multiple of type size. */
1608 if (dr_step && (dr_step % type_size) != 0)
1609 {
1610 if (vect_print_dump_info (REPORT_DETAILS))
1611 {
1612 fprintf (vect_dump, "step is not a multiple of type size: step ");
1613 print_generic_expr (vect_dump, step, TDF_SLIM);
1614 fprintf (vect_dump, " size ");
1615 print_generic_expr (vect_dump, TYPE_SIZE_UNIT (scalar_type),
1616 TDF_SLIM);
1617 }
1618 return false;
1619 }
1620
1621 /* FORNOW: we handle only interleaving that is a power of 2.
1622 We don't fail here if it may be still possible to vectorize the
1623 group using SLP. If not, the size of the group will be checked in
1624 vect_analyze_operations, and the vectorization will fail. */
1625 if (exact_log2 (stride) == -1)
1626 {
1627 if (vect_print_dump_info (REPORT_DETAILS))
1628 fprintf (vect_dump, "interleaving is not a power of 2");
1629
1630 if (slp_impossible)
1631 return false;
1632 }
1633
1634 if (stride == 0)
1635 stride = count;
1636
1637 DR_GROUP_SIZE (vinfo_for_stmt (stmt)) = stride;
1638 if (vect_print_dump_info (REPORT_DETAILS))
1639 fprintf (vect_dump, "Detected interleaving of size %d", (int)stride);
1640
1641 /* SLP: create an SLP data structure for every interleaving group of
1642 stores for further analysis in vect_analyse_slp. */
1643 if (!DR_IS_READ (dr) && !slp_impossible)
1644 {
1645 if (loop_vinfo)
1646 VEC_safe_push (gimple, heap, LOOP_VINFO_STRIDED_STORES (loop_vinfo),
1647 stmt);
1648 if (bb_vinfo)
1649 VEC_safe_push (gimple, heap, BB_VINFO_STRIDED_STORES (bb_vinfo),
1650 stmt);
1651 }
1652 }
1653
1654 return true;
1655 }
1656
1657
1658 /* Analyze the access pattern of the data-reference DR.
1659 In case of non-consecutive accesses call vect_analyze_group_access() to
1660 analyze groups of strided accesses. */
1661
1662 static bool
1663 vect_analyze_data_ref_access (struct data_reference *dr)
1664 {
1665 tree step = DR_STEP (dr);
1666 tree scalar_type = TREE_TYPE (DR_REF (dr));
1667 gimple stmt = DR_STMT (dr);
1668 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
1669 loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info);
1670 struct loop *loop = NULL;
1671 HOST_WIDE_INT dr_step = TREE_INT_CST_LOW (step);
1672
1673 if (loop_vinfo)
1674 loop = LOOP_VINFO_LOOP (loop_vinfo);
1675
1676 if (loop_vinfo && !step)
1677 {
1678 if (vect_print_dump_info (REPORT_DETAILS))
1679 fprintf (vect_dump, "bad data-ref access in loop");
1680 return false;
1681 }
1682
1683 /* Don't allow invariant accesses in loops. */
1684 if (loop_vinfo && dr_step == 0)
1685 return false;
1686
1687 if (loop && nested_in_vect_loop_p (loop, stmt))
1688 {
1689 /* Interleaved accesses are not yet supported within outer-loop
1690 vectorization for references in the inner-loop. */
1691 DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt)) = NULL;
1692
1693 /* For the rest of the analysis we use the outer-loop step. */
1694 step = STMT_VINFO_DR_STEP (stmt_info);
1695 dr_step = TREE_INT_CST_LOW (step);
1696
1697 if (dr_step == 0)
1698 {
1699 if (vect_print_dump_info (REPORT_ALIGNMENT))
1700 fprintf (vect_dump, "zero step in outer loop.");
1701 if (DR_IS_READ (dr))
1702 return true;
1703 else
1704 return false;
1705 }
1706 }
1707
1708 /* Consecutive? */
1709 if (!tree_int_cst_compare (step, TYPE_SIZE_UNIT (scalar_type)))
1710 {
1711 /* Mark that it is not interleaving. */
1712 DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt)) = NULL;
1713 return true;
1714 }
1715
1716 if (loop && nested_in_vect_loop_p (loop, stmt))
1717 {
1718 if (vect_print_dump_info (REPORT_ALIGNMENT))
1719 fprintf (vect_dump, "strided access in outer loop.");
1720 return false;
1721 }
1722
1723 /* Not consecutive access - check if it's a part of interleaving group. */
1724 return vect_analyze_group_access (dr);
1725 }
1726
1727
1728 /* Function vect_analyze_data_ref_accesses.
1729
1730 Analyze the access pattern of all the data references in the loop.
1731
1732 FORNOW: the only access pattern that is considered vectorizable is a
1733 simple step 1 (consecutive) access.
1734
1735 FORNOW: handle only arrays and pointer accesses. */
1736
1737 bool
1738 vect_analyze_data_ref_accesses (loop_vec_info loop_vinfo, bb_vec_info bb_vinfo)
1739 {
1740 unsigned int i;
1741 VEC (data_reference_p, heap) *datarefs;
1742 struct data_reference *dr;
1743
1744 if (vect_print_dump_info (REPORT_DETAILS))
1745 fprintf (vect_dump, "=== vect_analyze_data_ref_accesses ===");
1746
1747 if (loop_vinfo)
1748 datarefs = LOOP_VINFO_DATAREFS (loop_vinfo);
1749 else
1750 datarefs = BB_VINFO_DATAREFS (bb_vinfo);
1751
1752 for (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++)
1753 if (!vect_analyze_data_ref_access (dr))
1754 {
1755 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOCATIONS))
1756 fprintf (vect_dump, "not vectorized: complicated access pattern.");
1757 return false;
1758 }
1759
1760 return true;
1761 }
1762
1763 /* Function vect_prune_runtime_alias_test_list.
1764
1765 Prune a list of ddrs to be tested at run-time by versioning for alias.
1766 Return FALSE if resulting list of ddrs is longer then allowed by
1767 PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS, otherwise return TRUE. */
1768
1769 bool
1770 vect_prune_runtime_alias_test_list (loop_vec_info loop_vinfo)
1771 {
1772 VEC (ddr_p, heap) * ddrs =
1773 LOOP_VINFO_MAY_ALIAS_DDRS (loop_vinfo);
1774 unsigned i, j;
1775
1776 if (vect_print_dump_info (REPORT_DETAILS))
1777 fprintf (vect_dump, "=== vect_prune_runtime_alias_test_list ===");
1778
1779 for (i = 0; i < VEC_length (ddr_p, ddrs); )
1780 {
1781 bool found;
1782 ddr_p ddr_i;
1783
1784 ddr_i = VEC_index (ddr_p, ddrs, i);
1785 found = false;
1786
1787 for (j = 0; j < i; j++)
1788 {
1789 ddr_p ddr_j = VEC_index (ddr_p, ddrs, j);
1790
1791 if (vect_vfa_range_equal (ddr_i, ddr_j))
1792 {
1793 if (vect_print_dump_info (REPORT_DR_DETAILS))
1794 {
1795 fprintf (vect_dump, "found equal ranges ");
1796 print_generic_expr (vect_dump, DR_REF (DDR_A (ddr_i)), TDF_SLIM);
1797 fprintf (vect_dump, ", ");
1798 print_generic_expr (vect_dump, DR_REF (DDR_B (ddr_i)), TDF_SLIM);
1799 fprintf (vect_dump, " and ");
1800 print_generic_expr (vect_dump, DR_REF (DDR_A (ddr_j)), TDF_SLIM);
1801 fprintf (vect_dump, ", ");
1802 print_generic_expr (vect_dump, DR_REF (DDR_B (ddr_j)), TDF_SLIM);
1803 }
1804 found = true;
1805 break;
1806 }
1807 }
1808
1809 if (found)
1810 {
1811 VEC_ordered_remove (ddr_p, ddrs, i);
1812 continue;
1813 }
1814 i++;
1815 }
1816
1817 if (VEC_length (ddr_p, ddrs) >
1818 (unsigned) PARAM_VALUE (PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS))
1819 {
1820 if (vect_print_dump_info (REPORT_DR_DETAILS))
1821 {
1822 fprintf (vect_dump,
1823 "disable versioning for alias - max number of generated "
1824 "checks exceeded.");
1825 }
1826
1827 VEC_truncate (ddr_p, LOOP_VINFO_MAY_ALIAS_DDRS (loop_vinfo), 0);
1828
1829 return false;
1830 }
1831
1832 return true;
1833 }
1834
1835
1836 /* Function vect_analyze_data_refs.
1837
1838 Find all the data references in the loop or basic block.
1839
1840 The general structure of the analysis of data refs in the vectorizer is as
1841 follows:
1842 1- vect_analyze_data_refs(loop/bb): call
1843 compute_data_dependences_for_loop/bb to find and analyze all data-refs
1844 in the loop/bb and their dependences.
1845 2- vect_analyze_dependences(): apply dependence testing using ddrs.
1846 3- vect_analyze_drs_alignment(): check that ref_stmt.alignment is ok.
1847 4- vect_analyze_drs_access(): check that ref_stmt.step is ok.
1848
1849 */
1850
1851 bool
1852 vect_analyze_data_refs (loop_vec_info loop_vinfo, bb_vec_info bb_vinfo)
1853 {
1854 struct loop *loop = NULL;
1855 basic_block bb = NULL;
1856 unsigned int i;
1857 VEC (data_reference_p, heap) *datarefs;
1858 struct data_reference *dr;
1859 tree scalar_type;
1860
1861 if (vect_print_dump_info (REPORT_DETAILS))
1862 fprintf (vect_dump, "=== vect_analyze_data_refs ===\n");
1863
1864 if (loop_vinfo)
1865 {
1866 loop = LOOP_VINFO_LOOP (loop_vinfo);
1867 compute_data_dependences_for_loop (loop, true,
1868 &LOOP_VINFO_DATAREFS (loop_vinfo),
1869 &LOOP_VINFO_DDRS (loop_vinfo));
1870 datarefs = LOOP_VINFO_DATAREFS (loop_vinfo);
1871 }
1872 else
1873 {
1874 bb = BB_VINFO_BB (bb_vinfo);
1875 compute_data_dependences_for_bb (bb, true,
1876 &BB_VINFO_DATAREFS (bb_vinfo),
1877 &BB_VINFO_DDRS (bb_vinfo));
1878 datarefs = BB_VINFO_DATAREFS (bb_vinfo);
1879 }
1880
1881 /* Go through the data-refs, check that the analysis succeeded. Update pointer
1882 from stmt_vec_info struct to DR and vectype. */
1883
1884 for (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++)
1885 {
1886 gimple stmt;
1887 stmt_vec_info stmt_info;
1888 tree base, offset, init;
1889
1890 if (!dr || !DR_REF (dr))
1891 {
1892 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOCATIONS))
1893 fprintf (vect_dump, "not vectorized: unhandled data-ref ");
1894 return false;
1895 }
1896
1897 stmt = DR_STMT (dr);
1898 stmt_info = vinfo_for_stmt (stmt);
1899
1900 /* Check that analysis of the data-ref succeeded. */
1901 if (!DR_BASE_ADDRESS (dr) || !DR_OFFSET (dr) || !DR_INIT (dr)
1902 || !DR_STEP (dr))
1903 {
1904 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOCATIONS))
1905 {
1906 fprintf (vect_dump, "not vectorized: data ref analysis failed ");
1907 print_gimple_stmt (vect_dump, stmt, 0, TDF_SLIM);
1908 }
1909 return false;
1910 }
1911
1912 if (TREE_CODE (DR_BASE_ADDRESS (dr)) == INTEGER_CST)
1913 {
1914 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOCATIONS))
1915 fprintf (vect_dump, "not vectorized: base addr of dr is a "
1916 "constant");
1917 return false;
1918 }
1919
1920 base = unshare_expr (DR_BASE_ADDRESS (dr));
1921 offset = unshare_expr (DR_OFFSET (dr));
1922 init = unshare_expr (DR_INIT (dr));
1923
1924 /* Update DR field in stmt_vec_info struct. */
1925
1926 /* If the dataref is in an inner-loop of the loop that is considered for
1927 for vectorization, we also want to analyze the access relative to
1928 the outer-loop (DR contains information only relative to the
1929 inner-most enclosing loop). We do that by building a reference to the
1930 first location accessed by the inner-loop, and analyze it relative to
1931 the outer-loop. */
1932 if (loop && nested_in_vect_loop_p (loop, stmt))
1933 {
1934 tree outer_step, outer_base, outer_init;
1935 HOST_WIDE_INT pbitsize, pbitpos;
1936 tree poffset;
1937 enum machine_mode pmode;
1938 int punsignedp, pvolatilep;
1939 affine_iv base_iv, offset_iv;
1940 tree dinit;
1941
1942 /* Build a reference to the first location accessed by the
1943 inner-loop: *(BASE+INIT). (The first location is actually
1944 BASE+INIT+OFFSET, but we add OFFSET separately later). */
1945 tree inner_base = build_fold_indirect_ref
1946 (fold_build2 (POINTER_PLUS_EXPR,
1947 TREE_TYPE (base), base,
1948 fold_convert (sizetype, init)));
1949
1950 if (vect_print_dump_info (REPORT_DETAILS))
1951 {
1952 fprintf (vect_dump, "analyze in outer-loop: ");
1953 print_generic_expr (vect_dump, inner_base, TDF_SLIM);
1954 }
1955
1956 outer_base = get_inner_reference (inner_base, &pbitsize, &pbitpos,
1957 &poffset, &pmode, &punsignedp, &pvolatilep, false);
1958 gcc_assert (outer_base != NULL_TREE);
1959
1960 if (pbitpos % BITS_PER_UNIT != 0)
1961 {
1962 if (vect_print_dump_info (REPORT_DETAILS))
1963 fprintf (vect_dump, "failed: bit offset alignment.\n");
1964 return false;
1965 }
1966
1967 outer_base = build_fold_addr_expr (outer_base);
1968 if (!simple_iv (loop, loop_containing_stmt (stmt), outer_base,
1969 &base_iv, false))
1970 {
1971 if (vect_print_dump_info (REPORT_DETAILS))
1972 fprintf (vect_dump, "failed: evolution of base is not affine.\n");
1973 return false;
1974 }
1975
1976 if (offset)
1977 {
1978 if (poffset)
1979 poffset = fold_build2 (PLUS_EXPR, TREE_TYPE (offset), offset,
1980 poffset);
1981 else
1982 poffset = offset;
1983 }
1984
1985 if (!poffset)
1986 {
1987 offset_iv.base = ssize_int (0);
1988 offset_iv.step = ssize_int (0);
1989 }
1990 else if (!simple_iv (loop, loop_containing_stmt (stmt), poffset,
1991 &offset_iv, false))
1992 {
1993 if (vect_print_dump_info (REPORT_DETAILS))
1994 fprintf (vect_dump, "evolution of offset is not affine.\n");
1995 return false;
1996 }
1997
1998 outer_init = ssize_int (pbitpos / BITS_PER_UNIT);
1999 split_constant_offset (base_iv.base, &base_iv.base, &dinit);
2000 outer_init = size_binop (PLUS_EXPR, outer_init, dinit);
2001 split_constant_offset (offset_iv.base, &offset_iv.base, &dinit);
2002 outer_init = size_binop (PLUS_EXPR, outer_init, dinit);
2003
2004 outer_step = size_binop (PLUS_EXPR,
2005 fold_convert (ssizetype, base_iv.step),
2006 fold_convert (ssizetype, offset_iv.step));
2007
2008 STMT_VINFO_DR_STEP (stmt_info) = outer_step;
2009 /* FIXME: Use canonicalize_base_object_address (base_iv.base); */
2010 STMT_VINFO_DR_BASE_ADDRESS (stmt_info) = base_iv.base;
2011 STMT_VINFO_DR_INIT (stmt_info) = outer_init;
2012 STMT_VINFO_DR_OFFSET (stmt_info) =
2013 fold_convert (ssizetype, offset_iv.base);
2014 STMT_VINFO_DR_ALIGNED_TO (stmt_info) =
2015 size_int (highest_pow2_factor (offset_iv.base));
2016
2017 if (vect_print_dump_info (REPORT_DETAILS))
2018 {
2019 fprintf (vect_dump, "\touter base_address: ");
2020 print_generic_expr (vect_dump, STMT_VINFO_DR_BASE_ADDRESS (stmt_info), TDF_SLIM);
2021 fprintf (vect_dump, "\n\touter offset from base address: ");
2022 print_generic_expr (vect_dump, STMT_VINFO_DR_OFFSET (stmt_info), TDF_SLIM);
2023 fprintf (vect_dump, "\n\touter constant offset from base address: ");
2024 print_generic_expr (vect_dump, STMT_VINFO_DR_INIT (stmt_info), TDF_SLIM);
2025 fprintf (vect_dump, "\n\touter step: ");
2026 print_generic_expr (vect_dump, STMT_VINFO_DR_STEP (stmt_info), TDF_SLIM);
2027 fprintf (vect_dump, "\n\touter aligned to: ");
2028 print_generic_expr (vect_dump, STMT_VINFO_DR_ALIGNED_TO (stmt_info), TDF_SLIM);
2029 }
2030 }
2031
2032 if (STMT_VINFO_DATA_REF (stmt_info))
2033 {
2034 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOCATIONS))
2035 {
2036 fprintf (vect_dump,
2037 "not vectorized: more than one data ref in stmt: ");
2038 print_gimple_stmt (vect_dump, stmt, 0, TDF_SLIM);
2039 }
2040 return false;
2041 }
2042
2043 STMT_VINFO_DATA_REF (stmt_info) = dr;
2044
2045 /* Set vectype for STMT. */
2046 scalar_type = TREE_TYPE (DR_REF (dr));
2047 STMT_VINFO_VECTYPE (stmt_info) =
2048 get_vectype_for_scalar_type (scalar_type);
2049 if (!STMT_VINFO_VECTYPE (stmt_info))
2050 {
2051 if (vect_print_dump_info (REPORT_UNVECTORIZED_LOCATIONS))
2052 {
2053 fprintf (vect_dump,
2054 "not vectorized: no vectype for stmt: ");
2055 print_gimple_stmt (vect_dump, stmt, 0, TDF_SLIM);
2056 fprintf (vect_dump, " scalar_type: ");
2057 print_generic_expr (vect_dump, scalar_type, TDF_DETAILS);
2058 }
2059 return false;
2060 }
2061 }
2062
2063 return true;
2064 }
2065
2066
2067 /* Function vect_get_new_vect_var.
2068
2069 Returns a name for a new variable. The current naming scheme appends the
2070 prefix "vect_" or "vect_p" (depending on the value of VAR_KIND) to
2071 the name of vectorizer generated variables, and appends that to NAME if
2072 provided. */
2073
2074 tree
2075 vect_get_new_vect_var (tree type, enum vect_var_kind var_kind, const char *name)
2076 {
2077 const char *prefix;
2078 tree new_vect_var;
2079
2080 switch (var_kind)
2081 {
2082 case vect_simple_var:
2083 prefix = "vect_";
2084 break;
2085 case vect_scalar_var:
2086 prefix = "stmp_";
2087 break;
2088 case vect_pointer_var:
2089 prefix = "vect_p";
2090 break;
2091 default:
2092 gcc_unreachable ();
2093 }
2094
2095 if (name)
2096 {
2097 char* tmp = concat (prefix, name, NULL);
2098 new_vect_var = create_tmp_var (type, tmp);
2099 free (tmp);
2100 }
2101 else
2102 new_vect_var = create_tmp_var (type, prefix);
2103
2104 /* Mark vector typed variable as a gimple register variable. */
2105 if (TREE_CODE (type) == VECTOR_TYPE)
2106 DECL_GIMPLE_REG_P (new_vect_var) = true;
2107
2108 return new_vect_var;
2109 }
2110
2111
2112 /* Function vect_create_addr_base_for_vector_ref.
2113
2114 Create an expression that computes the address of the first memory location
2115 that will be accessed for a data reference.
2116
2117 Input:
2118 STMT: The statement containing the data reference.
2119 NEW_STMT_LIST: Must be initialized to NULL_TREE or a statement list.
2120 OFFSET: Optional. If supplied, it is be added to the initial address.
2121 LOOP: Specify relative to which loop-nest should the address be computed.
2122 For example, when the dataref is in an inner-loop nested in an
2123 outer-loop that is now being vectorized, LOOP can be either the
2124 outer-loop, or the inner-loop. The first memory location accessed
2125 by the following dataref ('in' points to short):
2126
2127 for (i=0; i<N; i++)
2128 for (j=0; j<M; j++)
2129 s += in[i+j]
2130
2131 is as follows:
2132 if LOOP=i_loop: &in (relative to i_loop)
2133 if LOOP=j_loop: &in+i*2B (relative to j_loop)
2134
2135 Output:
2136 1. Return an SSA_NAME whose value is the address of the memory location of
2137 the first vector of the data reference.
2138 2. If new_stmt_list is not NULL_TREE after return then the caller must insert
2139 these statement(s) which define the returned SSA_NAME.
2140
2141 FORNOW: We are only handling array accesses with step 1. */
2142
2143 tree
2144 vect_create_addr_base_for_vector_ref (gimple stmt,
2145 gimple_seq *new_stmt_list,
2146 tree offset,
2147 struct loop *loop)
2148 {
2149 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
2150 struct data_reference *dr = STMT_VINFO_DATA_REF (stmt_info);
2151 tree data_ref_base = unshare_expr (DR_BASE_ADDRESS (dr));
2152 tree base_name;
2153 tree data_ref_base_var;
2154 tree vec_stmt;
2155 tree addr_base, addr_expr;
2156 tree dest;
2157 gimple_seq seq = NULL;
2158 tree base_offset = unshare_expr (DR_OFFSET (dr));
2159 tree init = unshare_expr (DR_INIT (dr));
2160 tree vect_ptr_type;
2161 tree step = TYPE_SIZE_UNIT (TREE_TYPE (DR_REF (dr)));
2162 loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info);
2163
2164 if (loop_vinfo && loop && loop != (gimple_bb (stmt))->loop_father)
2165 {
2166 struct loop *outer_loop = LOOP_VINFO_LOOP (loop_vinfo);
2167
2168 gcc_assert (nested_in_vect_loop_p (outer_loop, stmt));
2169
2170 data_ref_base = unshare_expr (STMT_VINFO_DR_BASE_ADDRESS (stmt_info));
2171 base_offset = unshare_expr (STMT_VINFO_DR_OFFSET (stmt_info));
2172 init = unshare_expr (STMT_VINFO_DR_INIT (stmt_info));
2173 }
2174
2175 if (loop_vinfo)
2176 base_name = build_fold_indirect_ref (data_ref_base);
2177 else
2178 {
2179 base_offset = ssize_int (0);
2180 init = ssize_int (0);
2181 base_name = build_fold_indirect_ref (unshare_expr (DR_REF (dr)));
2182 }
2183
2184 data_ref_base_var = create_tmp_var (TREE_TYPE (data_ref_base), "batmp");
2185 add_referenced_var (data_ref_base_var);
2186 data_ref_base = force_gimple_operand (data_ref_base, &seq, true,
2187 data_ref_base_var);
2188 gimple_seq_add_seq (new_stmt_list, seq);
2189
2190 /* Create base_offset */
2191 base_offset = size_binop (PLUS_EXPR,
2192 fold_convert (sizetype, base_offset),
2193 fold_convert (sizetype, init));
2194 dest = create_tmp_var (sizetype, "base_off");
2195 add_referenced_var (dest);
2196 base_offset = force_gimple_operand (base_offset, &seq, true, dest);
2197 gimple_seq_add_seq (new_stmt_list, seq);
2198
2199 if (offset)
2200 {
2201 tree tmp = create_tmp_var (sizetype, "offset");
2202
2203 add_referenced_var (tmp);
2204 offset = fold_build2 (MULT_EXPR, sizetype,
2205 fold_convert (sizetype, offset), step);
2206 base_offset = fold_build2 (PLUS_EXPR, sizetype,
2207 base_offset, offset);
2208 base_offset = force_gimple_operand (base_offset, &seq, false, tmp);
2209 gimple_seq_add_seq (new_stmt_list, seq);
2210 }
2211
2212 /* base + base_offset */
2213 if (loop_vinfo)
2214 addr_base = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (data_ref_base),
2215 data_ref_base, base_offset);
2216 else
2217 {
2218 if (TREE_CODE (DR_REF (dr)) == INDIRECT_REF)
2219 addr_base = unshare_expr (TREE_OPERAND (DR_REF (dr), 0));
2220 else
2221 addr_base = build1 (ADDR_EXPR,
2222 build_pointer_type (TREE_TYPE (DR_REF (dr))),
2223 unshare_expr (DR_REF (dr)));
2224 }
2225
2226 vect_ptr_type = build_pointer_type (STMT_VINFO_VECTYPE (stmt_info));
2227
2228 vec_stmt = fold_convert (vect_ptr_type, addr_base);
2229 addr_expr = vect_get_new_vect_var (vect_ptr_type, vect_pointer_var,
2230 get_name (base_name));
2231 add_referenced_var (addr_expr);
2232 vec_stmt = force_gimple_operand (vec_stmt, &seq, false, addr_expr);
2233 gimple_seq_add_seq (new_stmt_list, seq);
2234
2235 if (vect_print_dump_info (REPORT_DETAILS))
2236 {
2237 fprintf (vect_dump, "created ");
2238 print_generic_expr (vect_dump, vec_stmt, TDF_SLIM);
2239 }
2240
2241 return vec_stmt;
2242 }
2243
2244
2245 /* Function vect_create_data_ref_ptr.
2246
2247 Create a new pointer to vector type (vp), that points to the first location
2248 accessed in the loop by STMT, along with the def-use update chain to
2249 appropriately advance the pointer through the loop iterations. Also set
2250 aliasing information for the pointer. This vector pointer is used by the
2251 callers to this function to create a memory reference expression for vector
2252 load/store access.
2253
2254 Input:
2255 1. STMT: a stmt that references memory. Expected to be of the form
2256 GIMPLE_ASSIGN <name, data-ref> or
2257 GIMPLE_ASSIGN <data-ref, name>.
2258 2. AT_LOOP: the loop where the vector memref is to be created.
2259 3. OFFSET (optional): an offset to be added to the initial address accessed
2260 by the data-ref in STMT.
2261 4. ONLY_INIT: indicate if vp is to be updated in the loop, or remain
2262 pointing to the initial address.
2263 5. TYPE: if not NULL indicates the required type of the data-ref.
2264
2265 Output:
2266 1. Declare a new ptr to vector_type, and have it point to the base of the
2267 data reference (initial addressed accessed by the data reference).
2268 For example, for vector of type V8HI, the following code is generated:
2269
2270 v8hi *vp;
2271 vp = (v8hi *)initial_address;
2272
2273 if OFFSET is not supplied:
2274 initial_address = &a[init];
2275 if OFFSET is supplied:
2276 initial_address = &a[init + OFFSET];
2277
2278 Return the initial_address in INITIAL_ADDRESS.
2279
2280 2. If ONLY_INIT is true, just return the initial pointer. Otherwise, also
2281 update the pointer in each iteration of the loop.
2282
2283 Return the increment stmt that updates the pointer in PTR_INCR.
2284
2285 3. Set INV_P to true if the access pattern of the data reference in the
2286 vectorized loop is invariant. Set it to false otherwise.
2287
2288 4. Return the pointer. */
2289
2290 tree
2291 vect_create_data_ref_ptr (gimple stmt, struct loop *at_loop,
2292 tree offset, tree *initial_address, gimple *ptr_incr,
2293 bool only_init, bool *inv_p)
2294 {
2295 tree base_name;
2296 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
2297 loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info);
2298 struct loop *loop = NULL;
2299 bool nested_in_vect_loop = false;
2300 struct loop *containing_loop = NULL;
2301 tree vectype = STMT_VINFO_VECTYPE (stmt_info);
2302 tree vect_ptr_type;
2303 tree vect_ptr;
2304 tree new_temp;
2305 gimple vec_stmt;
2306 gimple_seq new_stmt_list = NULL;
2307 edge pe = NULL;
2308 basic_block new_bb;
2309 tree vect_ptr_init;
2310 struct data_reference *dr = STMT_VINFO_DATA_REF (stmt_info);
2311 tree vptr;
2312 gimple_stmt_iterator incr_gsi;
2313 bool insert_after;
2314 tree indx_before_incr, indx_after_incr;
2315 gimple incr;
2316 tree step;
2317 bb_vec_info bb_vinfo = STMT_VINFO_BB_VINFO (stmt_info);
2318 gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
2319
2320 if (loop_vinfo)
2321 {
2322 loop = LOOP_VINFO_LOOP (loop_vinfo);
2323 nested_in_vect_loop = nested_in_vect_loop_p (loop, stmt);
2324 containing_loop = (gimple_bb (stmt))->loop_father;
2325 pe = loop_preheader_edge (loop);
2326 }
2327 else
2328 {
2329 gcc_assert (bb_vinfo);
2330 only_init = true;
2331 *ptr_incr = NULL;
2332 }
2333
2334 /* Check the step (evolution) of the load in LOOP, and record
2335 whether it's invariant. */
2336 if (nested_in_vect_loop)
2337 step = STMT_VINFO_DR_STEP (stmt_info);
2338 else
2339 step = DR_STEP (STMT_VINFO_DATA_REF (stmt_info));
2340
2341 if (tree_int_cst_compare (step, size_zero_node) == 0)
2342 *inv_p = true;
2343 else
2344 *inv_p = false;
2345
2346 /* Create an expression for the first address accessed by this load
2347 in LOOP. */
2348 base_name = build_fold_indirect_ref (unshare_expr (DR_BASE_ADDRESS (dr)));
2349
2350 if (vect_print_dump_info (REPORT_DETAILS))
2351 {
2352 tree data_ref_base = base_name;
2353 fprintf (vect_dump, "create vector-pointer variable to type: ");
2354 print_generic_expr (vect_dump, vectype, TDF_SLIM);
2355 if (TREE_CODE (data_ref_base) == VAR_DECL
2356 || TREE_CODE (data_ref_base) == ARRAY_REF)
2357 fprintf (vect_dump, " vectorizing an array ref: ");
2358 else if (TREE_CODE (data_ref_base) == COMPONENT_REF)
2359 fprintf (vect_dump, " vectorizing a record based array ref: ");
2360 else if (TREE_CODE (data_ref_base) == SSA_NAME)
2361 fprintf (vect_dump, " vectorizing a pointer ref: ");
2362 print_generic_expr (vect_dump, base_name, TDF_SLIM);
2363 }
2364
2365 /** (1) Create the new vector-pointer variable: **/
2366 vect_ptr_type = build_pointer_type (vectype);
2367 vect_ptr = vect_get_new_vect_var (vect_ptr_type, vect_pointer_var,
2368 get_name (base_name));
2369
2370 /* Vector types inherit the alias set of their component type by default so
2371 we need to use a ref-all pointer if the data reference does not conflict
2372 with the created vector data reference because it is not addressable. */
2373 if (!alias_sets_conflict_p (get_deref_alias_set (vect_ptr),
2374 get_alias_set (DR_REF (dr))))
2375 {
2376 vect_ptr_type
2377 = build_pointer_type_for_mode (vectype,
2378 TYPE_MODE (vect_ptr_type), true);
2379 vect_ptr = vect_get_new_vect_var (vect_ptr_type, vect_pointer_var,
2380 get_name (base_name));
2381 }
2382
2383 /* Likewise for any of the data references in the stmt group. */
2384 else if (STMT_VINFO_DR_GROUP_SIZE (stmt_info) > 1)
2385 {
2386 gimple orig_stmt = STMT_VINFO_DR_GROUP_FIRST_DR (stmt_info);
2387 do
2388 {
2389 tree lhs = gimple_assign_lhs (orig_stmt);
2390 if (!alias_sets_conflict_p (get_deref_alias_set (vect_ptr),
2391 get_alias_set (lhs)))
2392 {
2393 vect_ptr_type
2394 = build_pointer_type_for_mode (vectype,
2395 TYPE_MODE (vect_ptr_type), true);
2396 vect_ptr
2397 = vect_get_new_vect_var (vect_ptr_type, vect_pointer_var,
2398 get_name (base_name));
2399 break;
2400 }
2401
2402 orig_stmt = STMT_VINFO_DR_GROUP_NEXT_DR (vinfo_for_stmt (orig_stmt));
2403 }
2404 while (orig_stmt);
2405 }
2406
2407 add_referenced_var (vect_ptr);
2408
2409 /** Note: If the dataref is in an inner-loop nested in LOOP, and we are
2410 vectorizing LOOP (i.e. outer-loop vectorization), we need to create two
2411 def-use update cycles for the pointer: One relative to the outer-loop
2412 (LOOP), which is what steps (3) and (4) below do. The other is relative
2413 to the inner-loop (which is the inner-most loop containing the dataref),
2414 and this is done be step (5) below.
2415
2416 When vectorizing inner-most loops, the vectorized loop (LOOP) is also the
2417 inner-most loop, and so steps (3),(4) work the same, and step (5) is
2418 redundant. Steps (3),(4) create the following:
2419
2420 vp0 = &base_addr;
2421 LOOP: vp1 = phi(vp0,vp2)
2422 ...
2423 ...
2424 vp2 = vp1 + step
2425 goto LOOP
2426
2427 If there is an inner-loop nested in loop, then step (5) will also be
2428 applied, and an additional update in the inner-loop will be created:
2429
2430 vp0 = &base_addr;
2431 LOOP: vp1 = phi(vp0,vp2)
2432 ...
2433 inner: vp3 = phi(vp1,vp4)
2434 vp4 = vp3 + inner_step
2435 if () goto inner
2436 ...
2437 vp2 = vp1 + step
2438 if () goto LOOP */
2439
2440 /** (3) Calculate the initial address the vector-pointer, and set
2441 the vector-pointer to point to it before the loop: **/
2442
2443 /* Create: (&(base[init_val+offset]) in the loop preheader. */
2444
2445 new_temp = vect_create_addr_base_for_vector_ref (stmt, &new_stmt_list,
2446 offset, loop);
2447 if (new_stmt_list)
2448 {
2449 if (pe)
2450 {
2451 new_bb = gsi_insert_seq_on_edge_immediate (pe, new_stmt_list);
2452 gcc_assert (!new_bb);
2453 }
2454 else
2455 gsi_insert_seq_before (&gsi, new_stmt_list, GSI_SAME_STMT);
2456 }
2457
2458 *initial_address = new_temp;
2459
2460 /* Create: p = (vectype *) initial_base */
2461 vec_stmt = gimple_build_assign (vect_ptr,
2462 fold_convert (vect_ptr_type, new_temp));
2463 vect_ptr_init = make_ssa_name (vect_ptr, vec_stmt);
2464 gimple_assign_set_lhs (vec_stmt, vect_ptr_init);
2465 if (pe)
2466 {
2467 new_bb = gsi_insert_on_edge_immediate (pe, vec_stmt);
2468 gcc_assert (!new_bb);
2469 }
2470 else
2471 gsi_insert_before (&gsi, vec_stmt, GSI_SAME_STMT);
2472
2473 /** (4) Handle the updating of the vector-pointer inside the loop.
2474 This is needed when ONLY_INIT is false, and also when AT_LOOP
2475 is the inner-loop nested in LOOP (during outer-loop vectorization).
2476 **/
2477
2478 /* No update in loop is required. */
2479 if (only_init && (!loop_vinfo || at_loop == loop))
2480 {
2481 /* Copy the points-to information if it exists. */
2482 if (DR_PTR_INFO (dr))
2483 duplicate_ssa_name_ptr_info (vect_ptr_init, DR_PTR_INFO (dr));
2484 vptr = vect_ptr_init;
2485 }
2486 else
2487 {
2488 /* The step of the vector pointer is the Vector Size. */
2489 tree step = TYPE_SIZE_UNIT (vectype);
2490 /* One exception to the above is when the scalar step of the load in
2491 LOOP is zero. In this case the step here is also zero. */
2492 if (*inv_p)
2493 step = size_zero_node;
2494
2495 standard_iv_increment_position (loop, &incr_gsi, &insert_after);
2496
2497 create_iv (vect_ptr_init,
2498 fold_convert (vect_ptr_type, step),
2499 vect_ptr, loop, &incr_gsi, insert_after,
2500 &indx_before_incr, &indx_after_incr);
2501 incr = gsi_stmt (incr_gsi);
2502 set_vinfo_for_stmt (incr, new_stmt_vec_info (incr, loop_vinfo, NULL));
2503
2504 /* Copy the points-to information if it exists. */
2505 if (DR_PTR_INFO (dr))
2506 {
2507 duplicate_ssa_name_ptr_info (indx_before_incr, DR_PTR_INFO (dr));
2508 duplicate_ssa_name_ptr_info (indx_after_incr, DR_PTR_INFO (dr));
2509 }
2510 if (ptr_incr)
2511 *ptr_incr = incr;
2512
2513 vptr = indx_before_incr;
2514 }
2515
2516 if (!nested_in_vect_loop || only_init)
2517 return vptr;
2518
2519
2520 /** (5) Handle the updating of the vector-pointer inside the inner-loop
2521 nested in LOOP, if exists: **/
2522
2523 gcc_assert (nested_in_vect_loop);
2524 if (!only_init)
2525 {
2526 standard_iv_increment_position (containing_loop, &incr_gsi,
2527 &insert_after);
2528 create_iv (vptr, fold_convert (vect_ptr_type, DR_STEP (dr)), vect_ptr,
2529 containing_loop, &incr_gsi, insert_after, &indx_before_incr,
2530 &indx_after_incr);
2531 incr = gsi_stmt (incr_gsi);
2532 set_vinfo_for_stmt (incr, new_stmt_vec_info (incr, loop_vinfo, NULL));
2533
2534 /* Copy the points-to information if it exists. */
2535 if (DR_PTR_INFO (dr))
2536 {
2537 duplicate_ssa_name_ptr_info (indx_before_incr, DR_PTR_INFO (dr));
2538 duplicate_ssa_name_ptr_info (indx_after_incr, DR_PTR_INFO (dr));
2539 }
2540 if (ptr_incr)
2541 *ptr_incr = incr;
2542
2543 return indx_before_incr;
2544 }
2545 else
2546 gcc_unreachable ();
2547 }
2548
2549
2550 /* Function bump_vector_ptr
2551
2552 Increment a pointer (to a vector type) by vector-size. If requested,
2553 i.e. if PTR-INCR is given, then also connect the new increment stmt
2554 to the existing def-use update-chain of the pointer, by modifying
2555 the PTR_INCR as illustrated below:
2556
2557 The pointer def-use update-chain before this function:
2558 DATAREF_PTR = phi (p_0, p_2)
2559 ....
2560 PTR_INCR: p_2 = DATAREF_PTR + step
2561
2562 The pointer def-use update-chain after this function:
2563 DATAREF_PTR = phi (p_0, p_2)
2564 ....
2565 NEW_DATAREF_PTR = DATAREF_PTR + BUMP
2566 ....
2567 PTR_INCR: p_2 = NEW_DATAREF_PTR + step
2568
2569 Input:
2570 DATAREF_PTR - ssa_name of a pointer (to vector type) that is being updated
2571 in the loop.
2572 PTR_INCR - optional. The stmt that updates the pointer in each iteration of
2573 the loop. The increment amount across iterations is expected
2574 to be vector_size.
2575 BSI - location where the new update stmt is to be placed.
2576 STMT - the original scalar memory-access stmt that is being vectorized.
2577 BUMP - optional. The offset by which to bump the pointer. If not given,
2578 the offset is assumed to be vector_size.
2579
2580 Output: Return NEW_DATAREF_PTR as illustrated above.
2581
2582 */
2583
2584 tree
2585 bump_vector_ptr (tree dataref_ptr, gimple ptr_incr, gimple_stmt_iterator *gsi,
2586 gimple stmt, tree bump)
2587 {
2588 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
2589 struct data_reference *dr = STMT_VINFO_DATA_REF (stmt_info);
2590 tree vectype = STMT_VINFO_VECTYPE (stmt_info);
2591 tree ptr_var = SSA_NAME_VAR (dataref_ptr);
2592 tree update = TYPE_SIZE_UNIT (vectype);
2593 gimple incr_stmt;
2594 ssa_op_iter iter;
2595 use_operand_p use_p;
2596 tree new_dataref_ptr;
2597
2598 if (bump)
2599 update = bump;
2600
2601 incr_stmt = gimple_build_assign_with_ops (POINTER_PLUS_EXPR, ptr_var,
2602 dataref_ptr, update);
2603 new_dataref_ptr = make_ssa_name (ptr_var, incr_stmt);
2604 gimple_assign_set_lhs (incr_stmt, new_dataref_ptr);
2605 vect_finish_stmt_generation (stmt, incr_stmt, gsi);
2606
2607 /* Copy the points-to information if it exists. */
2608 if (DR_PTR_INFO (dr))
2609 duplicate_ssa_name_ptr_info (new_dataref_ptr, DR_PTR_INFO (dr));
2610
2611 if (!ptr_incr)
2612 return new_dataref_ptr;
2613
2614 /* Update the vector-pointer's cross-iteration increment. */
2615 FOR_EACH_SSA_USE_OPERAND (use_p, ptr_incr, iter, SSA_OP_USE)
2616 {
2617 tree use = USE_FROM_PTR (use_p);
2618
2619 if (use == dataref_ptr)
2620 SET_USE (use_p, new_dataref_ptr);
2621 else
2622 gcc_assert (tree_int_cst_compare (use, update) == 0);
2623 }
2624
2625 return new_dataref_ptr;
2626 }
2627
2628
2629 /* Function vect_create_destination_var.
2630
2631 Create a new temporary of type VECTYPE. */
2632
2633 tree
2634 vect_create_destination_var (tree scalar_dest, tree vectype)
2635 {
2636 tree vec_dest;
2637 const char *new_name;
2638 tree type;
2639 enum vect_var_kind kind;
2640
2641 kind = vectype ? vect_simple_var : vect_scalar_var;
2642 type = vectype ? vectype : TREE_TYPE (scalar_dest);
2643
2644 gcc_assert (TREE_CODE (scalar_dest) == SSA_NAME);
2645
2646 new_name = get_name (scalar_dest);
2647 if (!new_name)
2648 new_name = "var_";
2649 vec_dest = vect_get_new_vect_var (type, kind, new_name);
2650 add_referenced_var (vec_dest);
2651
2652 return vec_dest;
2653 }
2654
2655 /* Function vect_strided_store_supported.
2656
2657 Returns TRUE is INTERLEAVE_HIGH and INTERLEAVE_LOW operations are supported,
2658 and FALSE otherwise. */
2659
2660 bool
2661 vect_strided_store_supported (tree vectype)
2662 {
2663 optab interleave_high_optab, interleave_low_optab;
2664 int mode;
2665
2666 mode = (int) TYPE_MODE (vectype);
2667
2668 /* Check that the operation is supported. */
2669 interleave_high_optab = optab_for_tree_code (VEC_INTERLEAVE_HIGH_EXPR,
2670 vectype, optab_default);
2671 interleave_low_optab = optab_for_tree_code (VEC_INTERLEAVE_LOW_EXPR,
2672 vectype, optab_default);
2673 if (!interleave_high_optab || !interleave_low_optab)
2674 {
2675 if (vect_print_dump_info (REPORT_DETAILS))
2676 fprintf (vect_dump, "no optab for interleave.");
2677 return false;
2678 }
2679
2680 if (optab_handler (interleave_high_optab, mode)->insn_code
2681 == CODE_FOR_nothing
2682 || optab_handler (interleave_low_optab, mode)->insn_code
2683 == CODE_FOR_nothing)
2684 {
2685 if (vect_print_dump_info (REPORT_DETAILS))
2686 fprintf (vect_dump, "interleave op not supported by target.");
2687 return false;
2688 }
2689
2690 return true;
2691 }
2692
2693
2694 /* Function vect_permute_store_chain.
2695
2696 Given a chain of interleaved stores in DR_CHAIN of LENGTH that must be
2697 a power of 2, generate interleave_high/low stmts to reorder the data
2698 correctly for the stores. Return the final references for stores in
2699 RESULT_CHAIN.
2700
2701 E.g., LENGTH is 4 and the scalar type is short, i.e., VF is 8.
2702 The input is 4 vectors each containing 8 elements. We assign a number to each
2703 element, the input sequence is:
2704
2705 1st vec: 0 1 2 3 4 5 6 7
2706 2nd vec: 8 9 10 11 12 13 14 15
2707 3rd vec: 16 17 18 19 20 21 22 23
2708 4th vec: 24 25 26 27 28 29 30 31
2709
2710 The output sequence should be:
2711
2712 1st vec: 0 8 16 24 1 9 17 25
2713 2nd vec: 2 10 18 26 3 11 19 27
2714 3rd vec: 4 12 20 28 5 13 21 30
2715 4th vec: 6 14 22 30 7 15 23 31
2716
2717 i.e., we interleave the contents of the four vectors in their order.
2718
2719 We use interleave_high/low instructions to create such output. The input of
2720 each interleave_high/low operation is two vectors:
2721 1st vec 2nd vec
2722 0 1 2 3 4 5 6 7
2723 the even elements of the result vector are obtained left-to-right from the
2724 high/low elements of the first vector. The odd elements of the result are
2725 obtained left-to-right from the high/low elements of the second vector.
2726 The output of interleave_high will be: 0 4 1 5
2727 and of interleave_low: 2 6 3 7
2728
2729
2730 The permutation is done in log LENGTH stages. In each stage interleave_high
2731 and interleave_low stmts are created for each pair of vectors in DR_CHAIN,
2732 where the first argument is taken from the first half of DR_CHAIN and the
2733 second argument from it's second half.
2734 In our example,
2735
2736 I1: interleave_high (1st vec, 3rd vec)
2737 I2: interleave_low (1st vec, 3rd vec)
2738 I3: interleave_high (2nd vec, 4th vec)
2739 I4: interleave_low (2nd vec, 4th vec)
2740
2741 The output for the first stage is:
2742
2743 I1: 0 16 1 17 2 18 3 19
2744 I2: 4 20 5 21 6 22 7 23
2745 I3: 8 24 9 25 10 26 11 27
2746 I4: 12 28 13 29 14 30 15 31
2747
2748 The output of the second stage, i.e. the final result is:
2749
2750 I1: 0 8 16 24 1 9 17 25
2751 I2: 2 10 18 26 3 11 19 27
2752 I3: 4 12 20 28 5 13 21 30
2753 I4: 6 14 22 30 7 15 23 31. */
2754
2755 bool
2756 vect_permute_store_chain (VEC(tree,heap) *dr_chain,
2757 unsigned int length,
2758 gimple stmt,
2759 gimple_stmt_iterator *gsi,
2760 VEC(tree,heap) **result_chain)
2761 {
2762 tree perm_dest, vect1, vect2, high, low;
2763 gimple perm_stmt;
2764 tree vectype = STMT_VINFO_VECTYPE (vinfo_for_stmt (stmt));
2765 int i;
2766 unsigned int j;
2767 enum tree_code high_code, low_code;
2768
2769 /* Check that the operation is supported. */
2770 if (!vect_strided_store_supported (vectype))
2771 return false;
2772
2773 *result_chain = VEC_copy (tree, heap, dr_chain);
2774
2775 for (i = 0; i < exact_log2 (length); i++)
2776 {
2777 for (j = 0; j < length/2; j++)
2778 {
2779 vect1 = VEC_index (tree, dr_chain, j);
2780 vect2 = VEC_index (tree, dr_chain, j+length/2);
2781
2782 /* Create interleaving stmt:
2783 in the case of big endian:
2784 high = interleave_high (vect1, vect2)
2785 and in the case of little endian:
2786 high = interleave_low (vect1, vect2). */
2787 perm_dest = create_tmp_var (vectype, "vect_inter_high");
2788 DECL_GIMPLE_REG_P (perm_dest) = 1;
2789 add_referenced_var (perm_dest);
2790 if (BYTES_BIG_ENDIAN)
2791 {
2792 high_code = VEC_INTERLEAVE_HIGH_EXPR;
2793 low_code = VEC_INTERLEAVE_LOW_EXPR;
2794 }
2795 else
2796 {
2797 low_code = VEC_INTERLEAVE_HIGH_EXPR;
2798 high_code = VEC_INTERLEAVE_LOW_EXPR;
2799 }
2800 perm_stmt = gimple_build_assign_with_ops (high_code, perm_dest,
2801 vect1, vect2);
2802 high = make_ssa_name (perm_dest, perm_stmt);
2803 gimple_assign_set_lhs (perm_stmt, high);
2804 vect_finish_stmt_generation (stmt, perm_stmt, gsi);
2805 VEC_replace (tree, *result_chain, 2*j, high);
2806
2807 /* Create interleaving stmt:
2808 in the case of big endian:
2809 low = interleave_low (vect1, vect2)
2810 and in the case of little endian:
2811 low = interleave_high (vect1, vect2). */
2812 perm_dest = create_tmp_var (vectype, "vect_inter_low");
2813 DECL_GIMPLE_REG_P (perm_dest) = 1;
2814 add_referenced_var (perm_dest);
2815 perm_stmt = gimple_build_assign_with_ops (low_code, perm_dest,
2816 vect1, vect2);
2817 low = make_ssa_name (perm_dest, perm_stmt);
2818 gimple_assign_set_lhs (perm_stmt, low);
2819 vect_finish_stmt_generation (stmt, perm_stmt, gsi);
2820 VEC_replace (tree, *result_chain, 2*j+1, low);
2821 }
2822 dr_chain = VEC_copy (tree, heap, *result_chain);
2823 }
2824 return true;
2825 }
2826
2827 /* Function vect_setup_realignment
2828
2829 This function is called when vectorizing an unaligned load using
2830 the dr_explicit_realign[_optimized] scheme.
2831 This function generates the following code at the loop prolog:
2832
2833 p = initial_addr;
2834 x msq_init = *(floor(p)); # prolog load
2835 realignment_token = call target_builtin;
2836 loop:
2837 x msq = phi (msq_init, ---)
2838
2839 The stmts marked with x are generated only for the case of
2840 dr_explicit_realign_optimized.
2841
2842 The code above sets up a new (vector) pointer, pointing to the first
2843 location accessed by STMT, and a "floor-aligned" load using that pointer.
2844 It also generates code to compute the "realignment-token" (if the relevant
2845 target hook was defined), and creates a phi-node at the loop-header bb
2846 whose arguments are the result of the prolog-load (created by this
2847 function) and the result of a load that takes place in the loop (to be
2848 created by the caller to this function).
2849
2850 For the case of dr_explicit_realign_optimized:
2851 The caller to this function uses the phi-result (msq) to create the
2852 realignment code inside the loop, and sets up the missing phi argument,
2853 as follows:
2854 loop:
2855 msq = phi (msq_init, lsq)
2856 lsq = *(floor(p')); # load in loop
2857 result = realign_load (msq, lsq, realignment_token);
2858
2859 For the case of dr_explicit_realign:
2860 loop:
2861 msq = *(floor(p)); # load in loop
2862 p' = p + (VS-1);
2863 lsq = *(floor(p')); # load in loop
2864 result = realign_load (msq, lsq, realignment_token);
2865
2866 Input:
2867 STMT - (scalar) load stmt to be vectorized. This load accesses
2868 a memory location that may be unaligned.
2869 BSI - place where new code is to be inserted.
2870 ALIGNMENT_SUPPORT_SCHEME - which of the two misalignment handling schemes
2871 is used.
2872
2873 Output:
2874 REALIGNMENT_TOKEN - the result of a call to the builtin_mask_for_load
2875 target hook, if defined.
2876 Return value - the result of the loop-header phi node. */
2877
2878 tree
2879 vect_setup_realignment (gimple stmt, gimple_stmt_iterator *gsi,
2880 tree *realignment_token,
2881 enum dr_alignment_support alignment_support_scheme,
2882 tree init_addr,
2883 struct loop **at_loop)
2884 {
2885 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
2886 tree vectype = STMT_VINFO_VECTYPE (stmt_info);
2887 loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info);
2888 struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
2889 edge pe;
2890 tree scalar_dest = gimple_assign_lhs (stmt);
2891 tree vec_dest;
2892 gimple inc;
2893 tree ptr;
2894 tree data_ref;
2895 gimple new_stmt;
2896 basic_block new_bb;
2897 tree msq_init = NULL_TREE;
2898 tree new_temp;
2899 gimple phi_stmt;
2900 tree msq = NULL_TREE;
2901 gimple_seq stmts = NULL;
2902 bool inv_p;
2903 bool compute_in_loop = false;
2904 bool nested_in_vect_loop = nested_in_vect_loop_p (loop, stmt);
2905 struct loop *containing_loop = (gimple_bb (stmt))->loop_father;
2906 struct loop *loop_for_initial_load;
2907
2908 gcc_assert (alignment_support_scheme == dr_explicit_realign
2909 || alignment_support_scheme == dr_explicit_realign_optimized);
2910
2911 /* We need to generate three things:
2912 1. the misalignment computation
2913 2. the extra vector load (for the optimized realignment scheme).
2914 3. the phi node for the two vectors from which the realignment is
2915 done (for the optimized realignment scheme).
2916 */
2917
2918 /* 1. Determine where to generate the misalignment computation.
2919
2920 If INIT_ADDR is NULL_TREE, this indicates that the misalignment
2921 calculation will be generated by this function, outside the loop (in the
2922 preheader). Otherwise, INIT_ADDR had already been computed for us by the
2923 caller, inside the loop.
2924
2925 Background: If the misalignment remains fixed throughout the iterations of
2926 the loop, then both realignment schemes are applicable, and also the
2927 misalignment computation can be done outside LOOP. This is because we are
2928 vectorizing LOOP, and so the memory accesses in LOOP advance in steps that
2929 are a multiple of VS (the Vector Size), and therefore the misalignment in
2930 different vectorized LOOP iterations is always the same.
2931 The problem arises only if the memory access is in an inner-loop nested
2932 inside LOOP, which is now being vectorized using outer-loop vectorization.
2933 This is the only case when the misalignment of the memory access may not
2934 remain fixed throughout the iterations of the inner-loop (as explained in
2935 detail in vect_supportable_dr_alignment). In this case, not only is the
2936 optimized realignment scheme not applicable, but also the misalignment
2937 computation (and generation of the realignment token that is passed to
2938 REALIGN_LOAD) have to be done inside the loop.
2939
2940 In short, INIT_ADDR indicates whether we are in a COMPUTE_IN_LOOP mode
2941 or not, which in turn determines if the misalignment is computed inside
2942 the inner-loop, or outside LOOP. */
2943
2944 if (init_addr != NULL_TREE)
2945 {
2946 compute_in_loop = true;
2947 gcc_assert (alignment_support_scheme == dr_explicit_realign);
2948 }
2949
2950
2951 /* 2. Determine where to generate the extra vector load.
2952
2953 For the optimized realignment scheme, instead of generating two vector
2954 loads in each iteration, we generate a single extra vector load in the
2955 preheader of the loop, and in each iteration reuse the result of the
2956 vector load from the previous iteration. In case the memory access is in
2957 an inner-loop nested inside LOOP, which is now being vectorized using
2958 outer-loop vectorization, we need to determine whether this initial vector
2959 load should be generated at the preheader of the inner-loop, or can be
2960 generated at the preheader of LOOP. If the memory access has no evolution
2961 in LOOP, it can be generated in the preheader of LOOP. Otherwise, it has
2962 to be generated inside LOOP (in the preheader of the inner-loop). */
2963
2964 if (nested_in_vect_loop)
2965 {
2966 tree outerloop_step = STMT_VINFO_DR_STEP (stmt_info);
2967 bool invariant_in_outerloop =
2968 (tree_int_cst_compare (outerloop_step, size_zero_node) == 0);
2969 loop_for_initial_load = (invariant_in_outerloop ? loop : loop->inner);
2970 }
2971 else
2972 loop_for_initial_load = loop;
2973 if (at_loop)
2974 *at_loop = loop_for_initial_load;
2975
2976 /* 3. For the case of the optimized realignment, create the first vector
2977 load at the loop preheader. */
2978
2979 if (alignment_support_scheme == dr_explicit_realign_optimized)
2980 {
2981 /* Create msq_init = *(floor(p1)) in the loop preheader */
2982
2983 gcc_assert (!compute_in_loop);
2984 pe = loop_preheader_edge (loop_for_initial_load);
2985 vec_dest = vect_create_destination_var (scalar_dest, vectype);
2986 ptr = vect_create_data_ref_ptr (stmt, loop_for_initial_load, NULL_TREE,
2987 &init_addr, &inc, true, &inv_p);
2988 data_ref = build1 (ALIGN_INDIRECT_REF, vectype, ptr);
2989 new_stmt = gimple_build_assign (vec_dest, data_ref);
2990 new_temp = make_ssa_name (vec_dest, new_stmt);
2991 gimple_assign_set_lhs (new_stmt, new_temp);
2992 mark_symbols_for_renaming (new_stmt);
2993 new_bb = gsi_insert_on_edge_immediate (pe, new_stmt);
2994 gcc_assert (!new_bb);
2995 msq_init = gimple_assign_lhs (new_stmt);
2996 }
2997
2998 /* 4. Create realignment token using a target builtin, if available.
2999 It is done either inside the containing loop, or before LOOP (as
3000 determined above). */
3001
3002 if (targetm.vectorize.builtin_mask_for_load)
3003 {
3004 tree builtin_decl;
3005
3006 /* Compute INIT_ADDR - the initial addressed accessed by this memref. */
3007 if (compute_in_loop)
3008 gcc_assert (init_addr); /* already computed by the caller. */
3009 else
3010 {
3011 /* Generate the INIT_ADDR computation outside LOOP. */
3012 init_addr = vect_create_addr_base_for_vector_ref (stmt, &stmts,
3013 NULL_TREE, loop);
3014 pe = loop_preheader_edge (loop);
3015 new_bb = gsi_insert_seq_on_edge_immediate (pe, stmts);
3016 gcc_assert (!new_bb);
3017 }
3018
3019 builtin_decl = targetm.vectorize.builtin_mask_for_load ();
3020 new_stmt = gimple_build_call (builtin_decl, 1, init_addr);
3021 vec_dest =
3022 vect_create_destination_var (scalar_dest,
3023 gimple_call_return_type (new_stmt));
3024 new_temp = make_ssa_name (vec_dest, new_stmt);
3025 gimple_call_set_lhs (new_stmt, new_temp);
3026
3027 if (compute_in_loop)
3028 gsi_insert_before (gsi, new_stmt, GSI_SAME_STMT);
3029 else
3030 {
3031 /* Generate the misalignment computation outside LOOP. */
3032 pe = loop_preheader_edge (loop);
3033 new_bb = gsi_insert_on_edge_immediate (pe, new_stmt);
3034 gcc_assert (!new_bb);
3035 }
3036
3037 *realignment_token = gimple_call_lhs (new_stmt);
3038
3039 /* The result of the CALL_EXPR to this builtin is determined from
3040 the value of the parameter and no global variables are touched
3041 which makes the builtin a "const" function. Requiring the
3042 builtin to have the "const" attribute makes it unnecessary
3043 to call mark_call_clobbered. */
3044 gcc_assert (TREE_READONLY (builtin_decl));
3045 }
3046
3047 if (alignment_support_scheme == dr_explicit_realign)
3048 return msq;
3049
3050 gcc_assert (!compute_in_loop);
3051 gcc_assert (alignment_support_scheme == dr_explicit_realign_optimized);
3052
3053
3054 /* 5. Create msq = phi <msq_init, lsq> in loop */
3055
3056 pe = loop_preheader_edge (containing_loop);
3057 vec_dest = vect_create_destination_var (scalar_dest, vectype);
3058 msq = make_ssa_name (vec_dest, NULL);
3059 phi_stmt = create_phi_node (msq, containing_loop->header);
3060 SSA_NAME_DEF_STMT (msq) = phi_stmt;
3061 add_phi_arg (phi_stmt, msq_init, pe, UNKNOWN_LOCATION);
3062
3063 return msq;
3064 }
3065
3066
3067 /* Function vect_strided_load_supported.
3068
3069 Returns TRUE is EXTRACT_EVEN and EXTRACT_ODD operations are supported,
3070 and FALSE otherwise. */
3071
3072 bool
3073 vect_strided_load_supported (tree vectype)
3074 {
3075 optab perm_even_optab, perm_odd_optab;
3076 int mode;
3077
3078 mode = (int) TYPE_MODE (vectype);
3079
3080 perm_even_optab = optab_for_tree_code (VEC_EXTRACT_EVEN_EXPR, vectype,
3081 optab_default);
3082 if (!perm_even_optab)
3083 {
3084 if (vect_print_dump_info (REPORT_DETAILS))
3085 fprintf (vect_dump, "no optab for perm_even.");
3086 return false;
3087 }
3088
3089 if (optab_handler (perm_even_optab, mode)->insn_code == CODE_FOR_nothing)
3090 {
3091 if (vect_print_dump_info (REPORT_DETAILS))
3092 fprintf (vect_dump, "perm_even op not supported by target.");
3093 return false;
3094 }
3095
3096 perm_odd_optab = optab_for_tree_code (VEC_EXTRACT_ODD_EXPR, vectype,
3097 optab_default);
3098 if (!perm_odd_optab)
3099 {
3100 if (vect_print_dump_info (REPORT_DETAILS))
3101 fprintf (vect_dump, "no optab for perm_odd.");
3102 return false;
3103 }
3104
3105 if (optab_handler (perm_odd_optab, mode)->insn_code == CODE_FOR_nothing)
3106 {
3107 if (vect_print_dump_info (REPORT_DETAILS))
3108 fprintf (vect_dump, "perm_odd op not supported by target.");
3109 return false;
3110 }
3111 return true;
3112 }
3113
3114
3115 /* Function vect_permute_load_chain.
3116
3117 Given a chain of interleaved loads in DR_CHAIN of LENGTH that must be
3118 a power of 2, generate extract_even/odd stmts to reorder the input data
3119 correctly. Return the final references for loads in RESULT_CHAIN.
3120
3121 E.g., LENGTH is 4 and the scalar type is short, i.e., VF is 8.
3122 The input is 4 vectors each containing 8 elements. We assign a number to each
3123 element, the input sequence is:
3124
3125 1st vec: 0 1 2 3 4 5 6 7
3126 2nd vec: 8 9 10 11 12 13 14 15
3127 3rd vec: 16 17 18 19 20 21 22 23
3128 4th vec: 24 25 26 27 28 29 30 31
3129
3130 The output sequence should be:
3131
3132 1st vec: 0 4 8 12 16 20 24 28
3133 2nd vec: 1 5 9 13 17 21 25 29
3134 3rd vec: 2 6 10 14 18 22 26 30
3135 4th vec: 3 7 11 15 19 23 27 31
3136
3137 i.e., the first output vector should contain the first elements of each
3138 interleaving group, etc.
3139
3140 We use extract_even/odd instructions to create such output. The input of each
3141 extract_even/odd operation is two vectors
3142 1st vec 2nd vec
3143 0 1 2 3 4 5 6 7
3144
3145 and the output is the vector of extracted even/odd elements. The output of
3146 extract_even will be: 0 2 4 6
3147 and of extract_odd: 1 3 5 7
3148
3149
3150 The permutation is done in log LENGTH stages. In each stage extract_even and
3151 extract_odd stmts are created for each pair of vectors in DR_CHAIN in their
3152 order. In our example,
3153
3154 E1: extract_even (1st vec, 2nd vec)
3155 E2: extract_odd (1st vec, 2nd vec)
3156 E3: extract_even (3rd vec, 4th vec)
3157 E4: extract_odd (3rd vec, 4th vec)
3158
3159 The output for the first stage will be:
3160
3161 E1: 0 2 4 6 8 10 12 14
3162 E2: 1 3 5 7 9 11 13 15
3163 E3: 16 18 20 22 24 26 28 30
3164 E4: 17 19 21 23 25 27 29 31
3165
3166 In order to proceed and create the correct sequence for the next stage (or
3167 for the correct output, if the second stage is the last one, as in our
3168 example), we first put the output of extract_even operation and then the
3169 output of extract_odd in RESULT_CHAIN (which is then copied to DR_CHAIN).
3170 The input for the second stage is:
3171
3172 1st vec (E1): 0 2 4 6 8 10 12 14
3173 2nd vec (E3): 16 18 20 22 24 26 28 30
3174 3rd vec (E2): 1 3 5 7 9 11 13 15
3175 4th vec (E4): 17 19 21 23 25 27 29 31
3176
3177 The output of the second stage:
3178
3179 E1: 0 4 8 12 16 20 24 28
3180 E2: 2 6 10 14 18 22 26 30
3181 E3: 1 5 9 13 17 21 25 29
3182 E4: 3 7 11 15 19 23 27 31
3183
3184 And RESULT_CHAIN after reordering:
3185
3186 1st vec (E1): 0 4 8 12 16 20 24 28
3187 2nd vec (E3): 1 5 9 13 17 21 25 29
3188 3rd vec (E2): 2 6 10 14 18 22 26 30
3189 4th vec (E4): 3 7 11 15 19 23 27 31. */
3190
3191 bool
3192 vect_permute_load_chain (VEC(tree,heap) *dr_chain,
3193 unsigned int length,
3194 gimple stmt,
3195 gimple_stmt_iterator *gsi,
3196 VEC(tree,heap) **result_chain)
3197 {
3198 tree perm_dest, data_ref, first_vect, second_vect;
3199 gimple perm_stmt;
3200 tree vectype = STMT_VINFO_VECTYPE (vinfo_for_stmt (stmt));
3201 int i;
3202 unsigned int j;
3203
3204 /* Check that the operation is supported. */
3205 if (!vect_strided_load_supported (vectype))
3206 return false;
3207
3208 *result_chain = VEC_copy (tree, heap, dr_chain);
3209 for (i = 0; i < exact_log2 (length); i++)
3210 {
3211 for (j = 0; j < length; j +=2)
3212 {
3213 first_vect = VEC_index (tree, dr_chain, j);
3214 second_vect = VEC_index (tree, dr_chain, j+1);
3215
3216 /* data_ref = permute_even (first_data_ref, second_data_ref); */
3217 perm_dest = create_tmp_var (vectype, "vect_perm_even");
3218 DECL_GIMPLE_REG_P (perm_dest) = 1;
3219 add_referenced_var (perm_dest);
3220
3221 perm_stmt = gimple_build_assign_with_ops (VEC_EXTRACT_EVEN_EXPR,
3222 perm_dest, first_vect,
3223 second_vect);
3224
3225 data_ref = make_ssa_name (perm_dest, perm_stmt);
3226 gimple_assign_set_lhs (perm_stmt, data_ref);
3227 vect_finish_stmt_generation (stmt, perm_stmt, gsi);
3228 mark_symbols_for_renaming (perm_stmt);
3229
3230 VEC_replace (tree, *result_chain, j/2, data_ref);
3231
3232 /* data_ref = permute_odd (first_data_ref, second_data_ref); */
3233 perm_dest = create_tmp_var (vectype, "vect_perm_odd");
3234 DECL_GIMPLE_REG_P (perm_dest) = 1;
3235 add_referenced_var (perm_dest);
3236
3237 perm_stmt = gimple_build_assign_with_ops (VEC_EXTRACT_ODD_EXPR,
3238 perm_dest, first_vect,
3239 second_vect);
3240 data_ref = make_ssa_name (perm_dest, perm_stmt);
3241 gimple_assign_set_lhs (perm_stmt, data_ref);
3242 vect_finish_stmt_generation (stmt, perm_stmt, gsi);
3243 mark_symbols_for_renaming (perm_stmt);
3244
3245 VEC_replace (tree, *result_chain, j/2+length/2, data_ref);
3246 }
3247 dr_chain = VEC_copy (tree, heap, *result_chain);
3248 }
3249 return true;
3250 }
3251
3252
3253 /* Function vect_transform_strided_load.
3254
3255 Given a chain of input interleaved data-refs (in DR_CHAIN), build statements
3256 to perform their permutation and ascribe the result vectorized statements to
3257 the scalar statements.
3258 */
3259
3260 bool
3261 vect_transform_strided_load (gimple stmt, VEC(tree,heap) *dr_chain, int size,
3262 gimple_stmt_iterator *gsi)
3263 {
3264 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
3265 gimple first_stmt = DR_GROUP_FIRST_DR (stmt_info);
3266 gimple next_stmt, new_stmt;
3267 VEC(tree,heap) *result_chain = NULL;
3268 unsigned int i, gap_count;
3269 tree tmp_data_ref;
3270
3271 /* DR_CHAIN contains input data-refs that are a part of the interleaving.
3272 RESULT_CHAIN is the output of vect_permute_load_chain, it contains permuted
3273 vectors, that are ready for vector computation. */
3274 result_chain = VEC_alloc (tree, heap, size);
3275 /* Permute. */
3276 if (!vect_permute_load_chain (dr_chain, size, stmt, gsi, &result_chain))
3277 return false;
3278
3279 /* Put a permuted data-ref in the VECTORIZED_STMT field.
3280 Since we scan the chain starting from it's first node, their order
3281 corresponds the order of data-refs in RESULT_CHAIN. */
3282 next_stmt = first_stmt;
3283 gap_count = 1;
3284 for (i = 0; VEC_iterate (tree, result_chain, i, tmp_data_ref); i++)
3285 {
3286 if (!next_stmt)
3287 break;
3288
3289 /* Skip the gaps. Loads created for the gaps will be removed by dead
3290 code elimination pass later. No need to check for the first stmt in
3291 the group, since it always exists.
3292 DR_GROUP_GAP is the number of steps in elements from the previous
3293 access (if there is no gap DR_GROUP_GAP is 1). We skip loads that
3294 correspond to the gaps.
3295 */
3296 if (next_stmt != first_stmt
3297 && gap_count < DR_GROUP_GAP (vinfo_for_stmt (next_stmt)))
3298 {
3299 gap_count++;
3300 continue;
3301 }
3302
3303 while (next_stmt)
3304 {
3305 new_stmt = SSA_NAME_DEF_STMT (tmp_data_ref);
3306 /* We assume that if VEC_STMT is not NULL, this is a case of multiple
3307 copies, and we put the new vector statement in the first available
3308 RELATED_STMT. */
3309 if (!STMT_VINFO_VEC_STMT (vinfo_for_stmt (next_stmt)))
3310 STMT_VINFO_VEC_STMT (vinfo_for_stmt (next_stmt)) = new_stmt;
3311 else
3312 {
3313 if (!DR_GROUP_SAME_DR_STMT (vinfo_for_stmt (next_stmt)))
3314 {
3315 gimple prev_stmt =
3316 STMT_VINFO_VEC_STMT (vinfo_for_stmt (next_stmt));
3317 gimple rel_stmt =
3318 STMT_VINFO_RELATED_STMT (vinfo_for_stmt (prev_stmt));
3319 while (rel_stmt)
3320 {
3321 prev_stmt = rel_stmt;
3322 rel_stmt =
3323 STMT_VINFO_RELATED_STMT (vinfo_for_stmt (rel_stmt));
3324 }
3325
3326 STMT_VINFO_RELATED_STMT (vinfo_for_stmt (prev_stmt)) =
3327 new_stmt;
3328 }
3329 }
3330
3331 next_stmt = DR_GROUP_NEXT_DR (vinfo_for_stmt (next_stmt));
3332 gap_count = 1;
3333 /* If NEXT_STMT accesses the same DR as the previous statement,
3334 put the same TMP_DATA_REF as its vectorized statement; otherwise
3335 get the next data-ref from RESULT_CHAIN. */
3336 if (!next_stmt || !DR_GROUP_SAME_DR_STMT (vinfo_for_stmt (next_stmt)))
3337 break;
3338 }
3339 }
3340
3341 VEC_free (tree, heap, result_chain);
3342 return true;
3343 }
3344
3345 /* Function vect_force_dr_alignment_p.
3346
3347 Returns whether the alignment of a DECL can be forced to be aligned
3348 on ALIGNMENT bit boundary. */
3349
3350 bool
3351 vect_can_force_dr_alignment_p (const_tree decl, unsigned int alignment)
3352 {
3353 if (TREE_CODE (decl) != VAR_DECL)
3354 return false;
3355
3356 if (DECL_EXTERNAL (decl))
3357 return false;
3358
3359 if (TREE_ASM_WRITTEN (decl))
3360 return false;
3361
3362 if (TREE_STATIC (decl))
3363 return (alignment <= MAX_OFILE_ALIGNMENT);
3364 else
3365 return (alignment <= MAX_STACK_ALIGNMENT);
3366 }
3367
3368 /* Function vect_supportable_dr_alignment
3369
3370 Return whether the data reference DR is supported with respect to its
3371 alignment. */
3372
3373 enum dr_alignment_support
3374 vect_supportable_dr_alignment (struct data_reference *dr)
3375 {
3376 gimple stmt = DR_STMT (dr);
3377 stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
3378 tree vectype = STMT_VINFO_VECTYPE (stmt_info);
3379 enum machine_mode mode = TYPE_MODE (vectype);
3380 loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info);
3381 struct loop *vect_loop = NULL;
3382 bool nested_in_vect_loop = false;
3383
3384 if (aligned_access_p (dr))
3385 return dr_aligned;
3386
3387 if (!loop_vinfo)
3388 /* FORNOW: Misaligned accesses are supported only in loops. */
3389 return dr_unaligned_unsupported;
3390
3391 vect_loop = LOOP_VINFO_LOOP (loop_vinfo);
3392 nested_in_vect_loop = nested_in_vect_loop_p (vect_loop, stmt);
3393
3394 /* Possibly unaligned access. */
3395
3396 /* We can choose between using the implicit realignment scheme (generating
3397 a misaligned_move stmt) and the explicit realignment scheme (generating
3398 aligned loads with a REALIGN_LOAD). There are two variants to the explicit
3399 realignment scheme: optimized, and unoptimized.
3400 We can optimize the realignment only if the step between consecutive
3401 vector loads is equal to the vector size. Since the vector memory
3402 accesses advance in steps of VS (Vector Size) in the vectorized loop, it
3403 is guaranteed that the misalignment amount remains the same throughout the
3404 execution of the vectorized loop. Therefore, we can create the
3405 "realignment token" (the permutation mask that is passed to REALIGN_LOAD)
3406 at the loop preheader.
3407
3408 However, in the case of outer-loop vectorization, when vectorizing a
3409 memory access in the inner-loop nested within the LOOP that is now being
3410 vectorized, while it is guaranteed that the misalignment of the
3411 vectorized memory access will remain the same in different outer-loop
3412 iterations, it is *not* guaranteed that is will remain the same throughout
3413 the execution of the inner-loop. This is because the inner-loop advances
3414 with the original scalar step (and not in steps of VS). If the inner-loop
3415 step happens to be a multiple of VS, then the misalignment remains fixed
3416 and we can use the optimized realignment scheme. For example:
3417
3418 for (i=0; i<N; i++)
3419 for (j=0; j<M; j++)
3420 s += a[i+j];
3421
3422 When vectorizing the i-loop in the above example, the step between
3423 consecutive vector loads is 1, and so the misalignment does not remain
3424 fixed across the execution of the inner-loop, and the realignment cannot
3425 be optimized (as illustrated in the following pseudo vectorized loop):
3426
3427 for (i=0; i<N; i+=4)
3428 for (j=0; j<M; j++){
3429 vs += vp[i+j]; // misalignment of &vp[i+j] is {0,1,2,3,0,1,2,3,...}
3430 // when j is {0,1,2,3,4,5,6,7,...} respectively.
3431 // (assuming that we start from an aligned address).
3432 }
3433
3434 We therefore have to use the unoptimized realignment scheme:
3435
3436 for (i=0; i<N; i+=4)
3437 for (j=k; j<M; j+=4)
3438 vs += vp[i+j]; // misalignment of &vp[i+j] is always k (assuming
3439 // that the misalignment of the initial address is
3440 // 0).
3441
3442 The loop can then be vectorized as follows:
3443
3444 for (k=0; k<4; k++){
3445 rt = get_realignment_token (&vp[k]);
3446 for (i=0; i<N; i+=4){
3447 v1 = vp[i+k];
3448 for (j=k; j<M; j+=4){
3449 v2 = vp[i+j+VS-1];
3450 va = REALIGN_LOAD <v1,v2,rt>;
3451 vs += va;
3452 v1 = v2;
3453 }
3454 }
3455 } */
3456
3457 if (DR_IS_READ (dr))
3458 {
3459 bool is_packed = false;
3460 tree type = (TREE_TYPE (DR_REF (dr)));
3461
3462 if (optab_handler (vec_realign_load_optab, mode)->insn_code !=
3463 CODE_FOR_nothing
3464 && (!targetm.vectorize.builtin_mask_for_load
3465 || targetm.vectorize.builtin_mask_for_load ()))
3466 {
3467 tree vectype = STMT_VINFO_VECTYPE (stmt_info);
3468 if (nested_in_vect_loop
3469 && (TREE_INT_CST_LOW (DR_STEP (dr))
3470 != GET_MODE_SIZE (TYPE_MODE (vectype))))
3471 return dr_explicit_realign;
3472 else
3473 return dr_explicit_realign_optimized;
3474 }
3475 if (!known_alignment_for_access_p (dr))
3476 {
3477 tree ba = DR_BASE_OBJECT (dr);
3478
3479 if (ba)
3480 is_packed = contains_packed_reference (ba);
3481 }
3482
3483 if (targetm.vectorize.
3484 builtin_support_vector_misalignment (mode, type,
3485 DR_MISALIGNMENT (dr), is_packed))
3486 /* Can't software pipeline the loads, but can at least do them. */
3487 return dr_unaligned_supported;
3488 }
3489 else
3490 {
3491 bool is_packed = false;
3492 tree type = (TREE_TYPE (DR_REF (dr)));
3493
3494 if (!known_alignment_for_access_p (dr))
3495 {
3496 tree ba = DR_BASE_OBJECT (dr);
3497
3498 if (ba)
3499 is_packed = contains_packed_reference (ba);
3500 }
3501
3502 if (targetm.vectorize.
3503 builtin_support_vector_misalignment (mode, type,
3504 DR_MISALIGNMENT (dr), is_packed))
3505 return dr_unaligned_supported;
3506 }
3507
3508 /* Unsupported. */
3509 return dr_unaligned_unsupported;
3510 }