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2e681715 | 1 | /* Analysis Utilities for Loop Vectorization. |
f7064d11 DN |
2 | Copyright (C) 2003,2004,2005 Free Software Foundation, Inc. |
3 | Contributed by Dorit Naishlos <dorit@il.ibm.com> | |
4 | ||
5 | This file is part of GCC. | |
6 | ||
7 | GCC is free software; you can redistribute it and/or modify it under | |
8 | the terms of the GNU General Public License as published by the Free | |
9 | Software Foundation; either version 2, or (at your option) any later | |
10 | version. | |
11 | ||
12 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
13 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
14 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
15 | for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with GCC; see the file COPYING. If not, write to the Free | |
366ccddb KC |
19 | Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA |
20 | 02110-1301, USA. */ | |
f7064d11 DN |
21 | |
22 | #include "config.h" | |
23 | #include "system.h" | |
24 | #include "coretypes.h" | |
25 | #include "tm.h" | |
f7064d11 DN |
26 | #include "ggc.h" |
27 | #include "tree.h" | |
28 | #include "basic-block.h" | |
29 | #include "diagnostic.h" | |
30 | #include "tree-flow.h" | |
31 | #include "tree-dump.h" | |
32 | #include "timevar.h" | |
33 | #include "cfgloop.h" | |
34 | #include "expr.h" | |
35 | #include "optabs.h" | |
c12cc930 | 36 | #include "params.h" |
f7064d11 DN |
37 | #include "tree-chrec.h" |
38 | #include "tree-data-ref.h" | |
39 | #include "tree-scalar-evolution.h" | |
40 | #include "tree-vectorizer.h" | |
41 | ||
42 | /* Main analysis functions. */ | |
43 | static loop_vec_info vect_analyze_loop_form (struct loop *); | |
44 | static bool vect_analyze_data_refs (loop_vec_info); | |
45 | static bool vect_mark_stmts_to_be_vectorized (loop_vec_info); | |
88088c03 | 46 | static void vect_analyze_scalar_cycles (loop_vec_info); |
f7064d11 DN |
47 | static bool vect_analyze_data_ref_accesses (loop_vec_info); |
48 | static bool vect_analyze_data_ref_dependences (loop_vec_info); | |
49 | static bool vect_analyze_data_refs_alignment (loop_vec_info); | |
50 | static bool vect_compute_data_refs_alignment (loop_vec_info); | |
c12cc930 | 51 | static bool vect_enhance_data_refs_alignment (loop_vec_info); |
f7064d11 | 52 | static bool vect_analyze_operations (loop_vec_info); |
5f55a1ba | 53 | static bool vect_determine_vectorization_factor (loop_vec_info); |
f7064d11 DN |
54 | |
55 | /* Utility functions for the analyses. */ | |
56 | static bool exist_non_indexing_operands_for_use_p (tree, tree); | |
88088c03 DN |
57 | static void vect_mark_relevant (VEC(tree,heap) **, tree, bool, bool); |
58 | static bool vect_stmt_relevant_p (tree, loop_vec_info, bool *, bool *); | |
f7064d11 DN |
59 | static tree vect_get_loop_niters (struct loop *, tree *); |
60 | static bool vect_analyze_data_ref_dependence | |
86a07404 IR |
61 | (struct data_dependence_relation *, loop_vec_info); |
62 | static bool vect_compute_data_ref_alignment (struct data_reference *); | |
f7064d11 | 63 | static bool vect_analyze_data_ref_access (struct data_reference *); |
f7064d11 | 64 | static bool vect_can_advance_ivs_p (loop_vec_info); |
c12cc930 KB |
65 | static void vect_update_misalignment_for_peel |
66 | (struct data_reference *, struct data_reference *, int npeel); | |
67 | ||
f7064d11 | 68 | |
5f55a1ba DN |
69 | /* Function vect_determine_vectorization_factor |
70 | ||
71 | Determine the vectorization factor (VF). VF is the number of data elements | |
72 | that are operated upon in parallel in a single iteration of the vectorized | |
73 | loop. For example, when vectorizing a loop that operates on 4byte elements, | |
74 | on a target with vector size (VS) 16byte, the VF is set to 4, since 4 | |
75 | elements can fit in a single vector register. | |
76 | ||
77 | We currently support vectorization of loops in which all types operated upon | |
78 | are of the same size. Therefore this function currently sets VF according to | |
79 | the size of the types operated upon, and fails if there are multiple sizes | |
80 | in the loop. | |
81 | ||
82 | VF is also the factor by which the loop iterations are strip-mined, e.g.: | |
83 | original loop: | |
84 | for (i=0; i<N; i++){ | |
85 | a[i] = b[i] + c[i]; | |
86 | } | |
87 | ||
88 | vectorized loop: | |
89 | for (i=0; i<N; i+=VF){ | |
90 | a[i:VF] = b[i:VF] + c[i:VF]; | |
91 | } | |
92 | */ | |
93 | ||
94 | static bool | |
95 | vect_determine_vectorization_factor (loop_vec_info loop_vinfo) | |
96 | { | |
97 | struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); | |
98 | basic_block *bbs = LOOP_VINFO_BBS (loop_vinfo); | |
99 | int nbbs = loop->num_nodes; | |
100 | block_stmt_iterator si; | |
101 | unsigned int vectorization_factor = 0; | |
102 | int i; | |
103 | tree scalar_type; | |
104 | ||
00518cb1 | 105 | if (vect_print_dump_info (REPORT_DETAILS)) |
5f55a1ba DN |
106 | fprintf (vect_dump, "=== vect_determine_vectorization_factor ==="); |
107 | ||
108 | for (i = 0; i < nbbs; i++) | |
109 | { | |
110 | basic_block bb = bbs[i]; | |
111 | ||
112 | for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si)) | |
113 | { | |
114 | tree stmt = bsi_stmt (si); | |
115 | unsigned int nunits; | |
116 | stmt_vec_info stmt_info = vinfo_for_stmt (stmt); | |
117 | tree vectype; | |
118 | ||
00518cb1 | 119 | if (vect_print_dump_info (REPORT_DETAILS)) |
5f55a1ba DN |
120 | { |
121 | fprintf (vect_dump, "==> examining statement: "); | |
122 | print_generic_expr (vect_dump, stmt, TDF_SLIM); | |
123 | } | |
124 | ||
125 | gcc_assert (stmt_info); | |
126 | /* skip stmts which do not need to be vectorized. */ | |
88088c03 DN |
127 | if (!STMT_VINFO_RELEVANT_P (stmt_info) |
128 | && !STMT_VINFO_LIVE_P (stmt_info)) | |
129 | { | |
00518cb1 | 130 | if (vect_print_dump_info (REPORT_DETAILS)) |
88088c03 DN |
131 | fprintf (vect_dump, "skip."); |
132 | continue; | |
133 | } | |
5f55a1ba DN |
134 | |
135 | if (VECTOR_MODE_P (TYPE_MODE (TREE_TYPE (stmt)))) | |
136 | { | |
00518cb1 | 137 | if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS)) |
5f55a1ba DN |
138 | { |
139 | fprintf (vect_dump, "not vectorized: vector stmt in loop:"); | |
140 | print_generic_expr (vect_dump, stmt, TDF_SLIM); | |
141 | } | |
142 | return false; | |
143 | } | |
144 | ||
145 | if (STMT_VINFO_DATA_REF (stmt_info)) | |
146 | scalar_type = TREE_TYPE (DR_REF (STMT_VINFO_DATA_REF (stmt_info))); | |
147 | else if (TREE_CODE (stmt) == MODIFY_EXPR) | |
148 | scalar_type = TREE_TYPE (TREE_OPERAND (stmt, 0)); | |
149 | else | |
150 | scalar_type = TREE_TYPE (stmt); | |
151 | ||
00518cb1 | 152 | if (vect_print_dump_info (REPORT_DETAILS)) |
5f55a1ba DN |
153 | { |
154 | fprintf (vect_dump, "get vectype for scalar type: "); | |
155 | print_generic_expr (vect_dump, scalar_type, TDF_SLIM); | |
156 | } | |
157 | ||
158 | vectype = get_vectype_for_scalar_type (scalar_type); | |
159 | if (!vectype) | |
160 | { | |
00518cb1 | 161 | if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS)) |
5f55a1ba DN |
162 | { |
163 | fprintf (vect_dump, "not vectorized: unsupported data-type "); | |
164 | print_generic_expr (vect_dump, scalar_type, TDF_SLIM); | |
165 | } | |
166 | return false; | |
167 | } | |
00518cb1 | 168 | if (vect_print_dump_info (REPORT_DETAILS)) |
5f55a1ba DN |
169 | { |
170 | fprintf (vect_dump, "vectype: "); | |
171 | print_generic_expr (vect_dump, vectype, TDF_SLIM); | |
172 | } | |
173 | STMT_VINFO_VECTYPE (stmt_info) = vectype; | |
174 | ||
57d1677d | 175 | nunits = TYPE_VECTOR_SUBPARTS (vectype); |
00518cb1 | 176 | if (vect_print_dump_info (REPORT_DETAILS)) |
5f55a1ba DN |
177 | fprintf (vect_dump, "nunits = %d", nunits); |
178 | ||
179 | if (vectorization_factor) | |
180 | { | |
181 | /* FORNOW: don't allow mixed units. | |
182 | This restriction will be relaxed in the future. */ | |
183 | if (nunits != vectorization_factor) | |
184 | { | |
00518cb1 | 185 | if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS)) |
5f55a1ba DN |
186 | fprintf (vect_dump, "not vectorized: mixed data-types"); |
187 | return false; | |
188 | } | |
189 | } | |
190 | else | |
191 | vectorization_factor = nunits; | |
192 | ||
5f55a1ba DN |
193 | gcc_assert (GET_MODE_SIZE (TYPE_MODE (scalar_type)) |
194 | * vectorization_factor == UNITS_PER_SIMD_WORD); | |
5f55a1ba DN |
195 | } |
196 | } | |
197 | ||
198 | /* TODO: Analyze cost. Decide if worth while to vectorize. */ | |
199 | ||
200 | if (vectorization_factor <= 1) | |
201 | { | |
00518cb1 | 202 | if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS)) |
5f55a1ba DN |
203 | fprintf (vect_dump, "not vectorized: unsupported data-type"); |
204 | return false; | |
205 | } | |
206 | LOOP_VINFO_VECT_FACTOR (loop_vinfo) = vectorization_factor; | |
207 | ||
208 | return true; | |
209 | } | |
210 | ||
211 | ||
f7064d11 DN |
212 | /* Function vect_analyze_operations. |
213 | ||
214 | Scan the loop stmts and make sure they are all vectorizable. */ | |
215 | ||
216 | static bool | |
217 | vect_analyze_operations (loop_vec_info loop_vinfo) | |
218 | { | |
219 | struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); | |
220 | basic_block *bbs = LOOP_VINFO_BBS (loop_vinfo); | |
221 | int nbbs = loop->num_nodes; | |
222 | block_stmt_iterator si; | |
223 | unsigned int vectorization_factor = 0; | |
224 | int i; | |
225 | bool ok; | |
88088c03 DN |
226 | tree phi; |
227 | stmt_vec_info stmt_info; | |
228 | bool need_to_vectorize = false; | |
f7064d11 | 229 | |
00518cb1 | 230 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
231 | fprintf (vect_dump, "=== vect_analyze_operations ==="); |
232 | ||
5f55a1ba DN |
233 | gcc_assert (LOOP_VINFO_VECT_FACTOR (loop_vinfo)); |
234 | vectorization_factor = LOOP_VINFO_VECT_FACTOR (loop_vinfo); | |
235 | ||
f7064d11 DN |
236 | for (i = 0; i < nbbs; i++) |
237 | { | |
238 | basic_block bb = bbs[i]; | |
239 | ||
88088c03 DN |
240 | for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) |
241 | { | |
242 | stmt_info = vinfo_for_stmt (phi); | |
00518cb1 | 243 | if (vect_print_dump_info (REPORT_DETAILS)) |
88088c03 DN |
244 | { |
245 | fprintf (vect_dump, "examining phi: "); | |
246 | print_generic_expr (vect_dump, phi, TDF_SLIM); | |
247 | } | |
248 | ||
249 | gcc_assert (stmt_info); | |
250 | ||
251 | if (STMT_VINFO_LIVE_P (stmt_info)) | |
252 | { | |
253 | /* FORNOW: not yet supported. */ | |
00518cb1 | 254 | if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS)) |
88088c03 DN |
255 | fprintf (vect_dump, "not vectorized: value used after loop."); |
256 | return false; | |
257 | } | |
258 | ||
61d3cdbb DN |
259 | if (STMT_VINFO_RELEVANT_P (stmt_info)) |
260 | { | |
261 | /* Most likely a reduction-like computation that is used | |
262 | in the loop. */ | |
00518cb1 | 263 | if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS)) |
61d3cdbb DN |
264 | fprintf (vect_dump, "not vectorized: unsupported pattern."); |
265 | return false; | |
266 | } | |
267 | } | |
88088c03 | 268 | |
f7064d11 DN |
269 | for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si)) |
270 | { | |
271 | tree stmt = bsi_stmt (si); | |
f7064d11 | 272 | stmt_vec_info stmt_info = vinfo_for_stmt (stmt); |
f7064d11 | 273 | |
00518cb1 | 274 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
275 | { |
276 | fprintf (vect_dump, "==> examining statement: "); | |
277 | print_generic_expr (vect_dump, stmt, TDF_SLIM); | |
278 | } | |
279 | ||
280 | gcc_assert (stmt_info); | |
281 | ||
282 | /* skip stmts which do not need to be vectorized. | |
283 | this is expected to include: | |
284 | - the COND_EXPR which is the loop exit condition | |
285 | - any LABEL_EXPRs in the loop | |
286 | - computations that are used only for array indexing or loop | |
287 | control */ | |
288 | ||
88088c03 DN |
289 | if (!STMT_VINFO_RELEVANT_P (stmt_info) |
290 | && !STMT_VINFO_LIVE_P (stmt_info)) | |
f7064d11 | 291 | { |
00518cb1 | 292 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
293 | fprintf (vect_dump, "irrelevant."); |
294 | continue; | |
295 | } | |
296 | ||
5f55a1ba DN |
297 | if (STMT_VINFO_RELEVANT_P (stmt_info)) |
298 | { | |
299 | gcc_assert (!VECTOR_MODE_P (TYPE_MODE (TREE_TYPE (stmt)))); | |
300 | gcc_assert (STMT_VINFO_VECTYPE (stmt_info)); | |
f7064d11 | 301 | |
88088c03 DN |
302 | ok = (vectorizable_operation (stmt, NULL, NULL) |
303 | || vectorizable_assignment (stmt, NULL, NULL) | |
304 | || vectorizable_load (stmt, NULL, NULL) | |
305 | || vectorizable_store (stmt, NULL, NULL) | |
306 | || vectorizable_condition (stmt, NULL, NULL)); | |
307 | ||
308 | if (!ok) | |
309 | { | |
00518cb1 | 310 | if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS)) |
88088c03 DN |
311 | { |
312 | fprintf (vect_dump, | |
313 | "not vectorized: relevant stmt not supported: "); | |
314 | print_generic_expr (vect_dump, stmt, TDF_SLIM); | |
315 | } | |
316 | return false; | |
317 | } | |
318 | need_to_vectorize = true; | |
319 | } | |
f7064d11 | 320 | |
88088c03 | 321 | if (STMT_VINFO_LIVE_P (stmt_info)) |
f7064d11 | 322 | { |
61d3cdbb DN |
323 | ok = vectorizable_reduction (stmt, NULL, NULL); |
324 | ||
325 | if (ok) | |
326 | need_to_vectorize = true; | |
327 | else | |
328 | ok = vectorizable_live_operation (stmt, NULL, NULL); | |
88088c03 DN |
329 | |
330 | if (!ok) | |
f7064d11 | 331 | { |
00518cb1 | 332 | if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS)) |
88088c03 DN |
333 | { |
334 | fprintf (vect_dump, | |
335 | "not vectorized: live stmt not supported: "); | |
336 | print_generic_expr (vect_dump, stmt, TDF_SLIM); | |
337 | } | |
338 | return false; | |
f7064d11 | 339 | } |
f7064d11 | 340 | } |
88088c03 DN |
341 | } /* stmts in bb */ |
342 | } /* bbs */ | |
f7064d11 DN |
343 | |
344 | /* TODO: Analyze cost. Decide if worth while to vectorize. */ | |
345 | ||
88088c03 DN |
346 | /* All operations in the loop are either irrelevant (deal with loop |
347 | control, or dead), or only used outside the loop and can be moved | |
348 | out of the loop (e.g. invariants, inductions). The loop can be | |
349 | optimized away by scalar optimizations. We're better off not | |
350 | touching this loop. */ | |
351 | if (!need_to_vectorize) | |
352 | { | |
00518cb1 | 353 | if (vect_print_dump_info (REPORT_DETAILS)) |
88088c03 DN |
354 | fprintf (vect_dump, |
355 | "All the computation can be taken out of the loop."); | |
00518cb1 | 356 | if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS)) |
88088c03 DN |
357 | fprintf (vect_dump, |
358 | "not vectorized: redundant loop. no profit to vectorize."); | |
359 | return false; | |
360 | } | |
361 | ||
f7064d11 | 362 | if (LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo) |
00518cb1 | 363 | && vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
364 | fprintf (vect_dump, |
365 | "vectorization_factor = %d, niters = " HOST_WIDE_INT_PRINT_DEC, | |
366 | vectorization_factor, LOOP_VINFO_INT_NITERS (loop_vinfo)); | |
367 | ||
368 | if (LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo) | |
369 | && LOOP_VINFO_INT_NITERS (loop_vinfo) < vectorization_factor) | |
370 | { | |
00518cb1 | 371 | if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS)) |
f7064d11 DN |
372 | fprintf (vect_dump, "not vectorized: iteration count too small."); |
373 | return false; | |
374 | } | |
375 | ||
376 | if (!LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo) | |
c12cc930 KB |
377 | || LOOP_VINFO_INT_NITERS (loop_vinfo) % vectorization_factor != 0 |
378 | || LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo)) | |
f7064d11 | 379 | { |
00518cb1 | 380 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
381 | fprintf (vect_dump, "epilog loop required."); |
382 | if (!vect_can_advance_ivs_p (loop_vinfo)) | |
383 | { | |
00518cb1 | 384 | if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS)) |
f7064d11 DN |
385 | fprintf (vect_dump, |
386 | "not vectorized: can't create epilog loop 1."); | |
387 | return false; | |
388 | } | |
70388d94 | 389 | if (!slpeel_can_duplicate_loop_p (loop, loop->single_exit)) |
f7064d11 | 390 | { |
00518cb1 | 391 | if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS)) |
f7064d11 DN |
392 | fprintf (vect_dump, |
393 | "not vectorized: can't create epilog loop 2."); | |
394 | return false; | |
395 | } | |
396 | } | |
397 | ||
398 | return true; | |
399 | } | |
400 | ||
401 | ||
402 | /* Function exist_non_indexing_operands_for_use_p | |
403 | ||
404 | USE is one of the uses attached to STMT. Check if USE is | |
405 | used in STMT for anything other than indexing an array. */ | |
406 | ||
407 | static bool | |
408 | exist_non_indexing_operands_for_use_p (tree use, tree stmt) | |
409 | { | |
410 | tree operand; | |
411 | stmt_vec_info stmt_info = vinfo_for_stmt (stmt); | |
412 | ||
413 | /* USE corresponds to some operand in STMT. If there is no data | |
414 | reference in STMT, then any operand that corresponds to USE | |
415 | is not indexing an array. */ | |
416 | if (!STMT_VINFO_DATA_REF (stmt_info)) | |
417 | return true; | |
418 | ||
419 | /* STMT has a data_ref. FORNOW this means that its of one of | |
420 | the following forms: | |
421 | -1- ARRAY_REF = var | |
422 | -2- var = ARRAY_REF | |
423 | (This should have been verified in analyze_data_refs). | |
424 | ||
425 | 'var' in the second case corresponds to a def, not a use, | |
426 | so USE cannot correspond to any operands that are not used | |
427 | for array indexing. | |
428 | ||
429 | Therefore, all we need to check is if STMT falls into the | |
430 | first case, and whether var corresponds to USE. */ | |
431 | ||
432 | if (TREE_CODE (TREE_OPERAND (stmt, 0)) == SSA_NAME) | |
433 | return false; | |
434 | ||
435 | operand = TREE_OPERAND (stmt, 1); | |
436 | ||
437 | if (TREE_CODE (operand) != SSA_NAME) | |
438 | return false; | |
439 | ||
440 | if (operand == use) | |
441 | return true; | |
442 | ||
443 | return false; | |
444 | } | |
445 | ||
446 | ||
447 | /* Function vect_analyze_scalar_cycles. | |
448 | ||
449 | Examine the cross iteration def-use cycles of scalar variables, by | |
88088c03 DN |
450 | analyzing the loop (scalar) PHIs; Classify each cycle as one of the |
451 | following: invariant, induction, reduction, unknown. | |
452 | ||
453 | Some forms of scalar cycles are not yet supported. | |
454 | ||
455 | Example1: reduction: (unsupported yet) | |
f7064d11 | 456 | |
f7064d11 DN |
457 | loop1: |
458 | for (i=0; i<N; i++) | |
459 | sum += a[i]; | |
f7064d11 | 460 | |
88088c03 DN |
461 | Example2: induction: (unsupported yet) |
462 | ||
f7064d11 DN |
463 | loop2: |
464 | for (i=0; i<N; i++) | |
465 | a[i] = i; | |
466 | ||
88088c03 DN |
467 | Note: the following loop *is* vectorizable: |
468 | ||
f7064d11 DN |
469 | loop3: |
470 | for (i=0; i<N; i++) | |
471 | a[i] = b[i]; | |
472 | ||
88088c03 DN |
473 | even though it has a def-use cycle caused by the induction variable i: |
474 | ||
f7064d11 DN |
475 | loop: i_2 = PHI (i_0, i_1) |
476 | a[i_2] = ...; | |
477 | i_1 = i_2 + 1; | |
478 | GOTO loop; | |
479 | ||
88088c03 DN |
480 | because the def-use cycle in loop3 is considered "not relevant" - i.e., |
481 | it does not need to be vectorized because it is only used for array | |
482 | indexing (see 'mark_stmts_to_be_vectorized'). The def-use cycle in | |
483 | loop2 on the other hand is relevant (it is being written to memory). | |
484 | */ | |
f7064d11 | 485 | |
88088c03 | 486 | static void |
f7064d11 DN |
487 | vect_analyze_scalar_cycles (loop_vec_info loop_vinfo) |
488 | { | |
489 | tree phi; | |
490 | struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); | |
491 | basic_block bb = loop->header; | |
492 | tree dummy; | |
493 | ||
00518cb1 | 494 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
495 | fprintf (vect_dump, "=== vect_analyze_scalar_cycles ==="); |
496 | ||
497 | for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) | |
498 | { | |
499 | tree access_fn = NULL; | |
88088c03 DN |
500 | tree def = PHI_RESULT (phi); |
501 | stmt_vec_info stmt_vinfo = vinfo_for_stmt (phi); | |
502 | tree reduc_stmt; | |
f7064d11 | 503 | |
00518cb1 | 504 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
505 | { |
506 | fprintf (vect_dump, "Analyze phi: "); | |
507 | print_generic_expr (vect_dump, phi, TDF_SLIM); | |
508 | } | |
509 | ||
510 | /* Skip virtual phi's. The data dependences that are associated with | |
511 | virtual defs/uses (i.e., memory accesses) are analyzed elsewhere. */ | |
512 | ||
88088c03 | 513 | if (!is_gimple_reg (SSA_NAME_VAR (def))) |
f7064d11 | 514 | { |
00518cb1 | 515 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
516 | fprintf (vect_dump, "virtual phi. skip."); |
517 | continue; | |
518 | } | |
519 | ||
88088c03 | 520 | STMT_VINFO_DEF_TYPE (stmt_vinfo) = vect_unknown_def_type; |
f7064d11 | 521 | |
88088c03 | 522 | /* Analyze the evolution function. */ |
f7064d11 | 523 | |
88088c03 | 524 | access_fn = analyze_scalar_evolution (loop, def); |
f7064d11 DN |
525 | |
526 | if (!access_fn) | |
88088c03 | 527 | continue; |
f7064d11 | 528 | |
00518cb1 | 529 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
530 | { |
531 | fprintf (vect_dump, "Access function of PHI: "); | |
532 | print_generic_expr (vect_dump, access_fn, TDF_SLIM); | |
533 | } | |
534 | ||
88088c03 | 535 | if (vect_is_simple_iv_evolution (loop->num, access_fn, &dummy, &dummy)) |
f7064d11 | 536 | { |
00518cb1 | 537 | if (vect_print_dump_info (REPORT_DETAILS)) |
88088c03 DN |
538 | fprintf (vect_dump, "Detected induction."); |
539 | STMT_VINFO_DEF_TYPE (stmt_vinfo) = vect_induction_def; | |
540 | continue; | |
f7064d11 | 541 | } |
88088c03 DN |
542 | |
543 | /* TODO: handle invariant phis */ | |
544 | ||
545 | reduc_stmt = vect_is_simple_reduction (loop, phi); | |
546 | if (reduc_stmt) | |
547 | { | |
00518cb1 | 548 | if (vect_print_dump_info (REPORT_DETAILS)) |
88088c03 DN |
549 | fprintf (vect_dump, "Detected reduction."); |
550 | STMT_VINFO_DEF_TYPE (stmt_vinfo) = vect_reduction_def; | |
551 | STMT_VINFO_DEF_TYPE (vinfo_for_stmt (reduc_stmt)) = | |
552 | vect_reduction_def; | |
553 | } | |
554 | else | |
00518cb1 | 555 | if (vect_print_dump_info (REPORT_DETAILS)) |
88088c03 DN |
556 | fprintf (vect_dump, "Unknown def-use cycle pattern."); |
557 | ||
f7064d11 DN |
558 | } |
559 | ||
88088c03 | 560 | return; |
f7064d11 DN |
561 | } |
562 | ||
563 | ||
f7064d11 DN |
564 | /* Function vect_analyze_data_ref_dependence. |
565 | ||
566 | Return TRUE if there (might) exist a dependence between a memory-reference | |
567 | DRA and a memory-reference DRB. */ | |
86a07404 | 568 | |
f7064d11 | 569 | static bool |
86a07404 IR |
570 | vect_analyze_data_ref_dependence (struct data_dependence_relation *ddr, |
571 | loop_vec_info loop_vinfo) | |
f7064d11 | 572 | { |
b52485c6 DP |
573 | struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); |
574 | int vectorization_factor = LOOP_VINFO_VECT_FACTOR (loop_vinfo); | |
575 | int dist = 0; | |
576 | unsigned int loop_depth = 0; | |
86a07404 IR |
577 | struct loop *loop_nest = loop; |
578 | struct data_reference *dra = DDR_A (ddr); | |
579 | struct data_reference *drb = DDR_B (ddr); | |
580 | stmt_vec_info stmtinfo_a = vinfo_for_stmt (DR_STMT (dra)); | |
bb748329 | 581 | stmt_vec_info stmtinfo_b = vinfo_for_stmt (DR_STMT (drb)); |
86a07404 IR |
582 | |
583 | if (DDR_ARE_DEPENDENT (ddr) == chrec_known) | |
584 | return false; | |
f7064d11 | 585 | |
86a07404 | 586 | if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know) |
f7064d11 | 587 | { |
00518cb1 | 588 | if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS)) |
f7064d11 DN |
589 | { |
590 | fprintf (vect_dump, | |
86a07404 | 591 | "not vectorized: can't determine dependence between "); |
f7064d11 DN |
592 | print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM); |
593 | fprintf (vect_dump, " and "); | |
594 | print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM); | |
595 | } | |
596 | return true; | |
597 | } | |
598 | ||
86a07404 | 599 | if (!DDR_DIST_VECT (ddr)) |
b52485c6 | 600 | { |
00518cb1 | 601 | if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS)) |
b52485c6 | 602 | { |
86a07404 | 603 | fprintf (vect_dump, "not vectorized: bad dist vector for "); |
b52485c6 DP |
604 | print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM); |
605 | fprintf (vect_dump, " and "); | |
606 | print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM); | |
607 | } | |
608 | return true; | |
86a07404 | 609 | } |
b52485c6 DP |
610 | |
611 | /* Find loop depth. */ | |
86a07404 | 612 | while (loop_nest && loop_nest->outer && loop_nest->outer->outer) |
b52485c6 | 613 | { |
86a07404 IR |
614 | loop_nest = loop_nest->outer; |
615 | loop_depth++; | |
b52485c6 | 616 | } |
86a07404 | 617 | |
b52485c6 | 618 | dist = DDR_DIST_VECT (ddr)[loop_depth]; |
86a07404 IR |
619 | if (vect_print_dump_info (REPORT_DR_DETAILS)) |
620 | fprintf (vect_dump, "dependence distance = %d.",dist); | |
b52485c6 DP |
621 | |
622 | /* Same loop iteration. */ | |
bb748329 | 623 | if (dist % vectorization_factor == 0) |
b52485c6 | 624 | { |
bb748329 DN |
625 | /* Two references with distance zero have the same alignment. */ |
626 | VEC_safe_push (dr_p, heap, STMT_VINFO_SAME_ALIGN_REFS (stmtinfo_a), drb); | |
627 | VEC_safe_push (dr_p, heap, STMT_VINFO_SAME_ALIGN_REFS (stmtinfo_b), dra); | |
00518cb1 | 628 | if (vect_print_dump_info (REPORT_ALIGNMENT)) |
86a07404 IR |
629 | fprintf (vect_dump, "accesses have the same alignment."); |
630 | if (vect_print_dump_info (REPORT_DR_DETAILS)) | |
631 | { | |
632 | fprintf (vect_dump, "dependence distance modulo vf == 0 between "); | |
633 | print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM); | |
634 | fprintf (vect_dump, " and "); | |
635 | print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM); | |
636 | } | |
b52485c6 | 637 | return false; |
86a07404 | 638 | } |
b52485c6 | 639 | |
86a07404 IR |
640 | if (abs (dist) >= vectorization_factor) |
641 | { | |
642 | /* Dependence distance does not create dependence, as far as vectorization | |
643 | is concerned, in this case. */ | |
644 | if (vect_print_dump_info (REPORT_DR_DETAILS)) | |
645 | fprintf (vect_dump, "dependence distance >= VF."); | |
646 | return false; | |
647 | } | |
648 | ||
00518cb1 | 649 | if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS)) |
f7064d11 DN |
650 | { |
651 | fprintf (vect_dump, | |
86a07404 | 652 | "not vectorized: possible dependence between data-refs "); |
f7064d11 DN |
653 | print_generic_expr (vect_dump, DR_REF (dra), TDF_SLIM); |
654 | fprintf (vect_dump, " and "); | |
655 | print_generic_expr (vect_dump, DR_REF (drb), TDF_SLIM); | |
656 | } | |
86a07404 | 657 | |
f7064d11 DN |
658 | return true; |
659 | } | |
660 | ||
661 | ||
662 | /* Function vect_analyze_data_ref_dependences. | |
86a07404 | 663 | |
f7064d11 | 664 | Examine all the data references in the loop, and make sure there do not |
b52485c6 | 665 | exist any data dependences between them. */ |
86a07404 | 666 | |
f7064d11 DN |
667 | static bool |
668 | vect_analyze_data_ref_dependences (loop_vec_info loop_vinfo) | |
669 | { | |
86a07404 IR |
670 | unsigned int i; |
671 | varray_type ddrs = LOOP_VINFO_DDRS (loop_vinfo); | |
f7064d11 | 672 | |
86a07404 | 673 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 | 674 | fprintf (vect_dump, "=== vect_analyze_dependences ==="); |
86a07404 IR |
675 | |
676 | for (i = 0; i < VARRAY_ACTIVE_SIZE (ddrs); i++) | |
f7064d11 | 677 | { |
86a07404 IR |
678 | struct data_dependence_relation *ddr = VARRAY_GENERIC_PTR (ddrs, i); |
679 | ||
680 | if (vect_analyze_data_ref_dependence (ddr, loop_vinfo)) | |
681 | return false; | |
f7064d11 DN |
682 | } |
683 | ||
684 | return true; | |
685 | } | |
686 | ||
687 | ||
688 | /* Function vect_compute_data_ref_alignment | |
689 | ||
690 | Compute the misalignment of the data reference DR. | |
691 | ||
692 | Output: | |
693 | 1. If during the misalignment computation it is found that the data reference | |
694 | cannot be vectorized then false is returned. | |
695 | 2. DR_MISALIGNMENT (DR) is defined. | |
696 | ||
697 | FOR NOW: No analysis is actually performed. Misalignment is calculated | |
698 | only for trivial cases. TODO. */ | |
699 | ||
700 | static bool | |
701 | vect_compute_data_ref_alignment (struct data_reference *dr) | |
702 | { | |
703 | tree stmt = DR_STMT (dr); | |
704 | stmt_vec_info stmt_info = vinfo_for_stmt (stmt); | |
705 | tree ref = DR_REF (dr); | |
706 | tree vectype; | |
86a07404 IR |
707 | tree base, base_addr; |
708 | bool base_aligned; | |
f7064d11 | 709 | tree misalign; |
86a07404 | 710 | tree aligned_to, alignment; |
f7064d11 | 711 | |
00518cb1 | 712 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
713 | fprintf (vect_dump, "vect_compute_data_ref_alignment:"); |
714 | ||
715 | /* Initialize misalignment to unknown. */ | |
716 | DR_MISALIGNMENT (dr) = -1; | |
717 | ||
86a07404 IR |
718 | misalign = DR_OFFSET_MISALIGNMENT (dr); |
719 | aligned_to = DR_ALIGNED_TO (dr); | |
720 | base_addr = DR_BASE_ADDRESS (dr); | |
721 | base = build_fold_indirect_ref (base_addr); | |
f7064d11 | 722 | vectype = STMT_VINFO_VECTYPE (stmt_info); |
86a07404 | 723 | alignment = ssize_int (TYPE_ALIGN (vectype)/BITS_PER_UNIT); |
f7064d11 | 724 | |
86a07404 IR |
725 | if ((aligned_to && tree_int_cst_compare (aligned_to, alignment) < 0) |
726 | || !misalign) | |
f7064d11 | 727 | { |
00518cb1 | 728 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
729 | { |
730 | fprintf (vect_dump, "Unknown alignment for access: "); | |
731 | print_generic_expr (vect_dump, base, TDF_SLIM); | |
732 | } | |
733 | return true; | |
734 | } | |
735 | ||
86a07404 IR |
736 | if ((DECL_P (base) |
737 | && tree_int_cst_compare (ssize_int (DECL_ALIGN_UNIT (base)), | |
738 | alignment) >= 0) | |
739 | || (TREE_CODE (base_addr) == SSA_NAME | |
740 | && tree_int_cst_compare (ssize_int (TYPE_ALIGN_UNIT (TREE_TYPE ( | |
741 | TREE_TYPE (base_addr)))), | |
742 | alignment) >= 0)) | |
743 | base_aligned = true; | |
744 | else | |
745 | base_aligned = false; | |
746 | ||
747 | if (!base_aligned) | |
f7064d11 DN |
748 | { |
749 | if (!vect_can_force_dr_alignment_p (base, TYPE_ALIGN (vectype))) | |
750 | { | |
00518cb1 | 751 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
752 | { |
753 | fprintf (vect_dump, "can't force alignment of ref: "); | |
754 | print_generic_expr (vect_dump, ref, TDF_SLIM); | |
755 | } | |
756 | return true; | |
757 | } | |
758 | ||
759 | /* Force the alignment of the decl. | |
760 | NOTE: This is the only change to the code we make during | |
761 | the analysis phase, before deciding to vectorize the loop. */ | |
00518cb1 | 762 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
763 | fprintf (vect_dump, "force alignment"); |
764 | DECL_ALIGN (base) = TYPE_ALIGN (vectype); | |
765 | DECL_USER_ALIGN (base) = 1; | |
766 | } | |
767 | ||
768 | /* At this point we assume that the base is aligned. */ | |
86a07404 | 769 | gcc_assert (base_aligned |
f7064d11 DN |
770 | || (TREE_CODE (base) == VAR_DECL |
771 | && DECL_ALIGN (base) >= TYPE_ALIGN (vectype))); | |
772 | ||
f7064d11 DN |
773 | /* Modulo alignment. */ |
774 | misalign = size_binop (TRUNC_MOD_EXPR, misalign, alignment); | |
86a07404 | 775 | |
9b14a362 | 776 | if (!host_integerp (misalign, 1)) |
f7064d11 | 777 | { |
9b14a362 | 778 | /* Negative or overflowed misalignment value. */ |
00518cb1 | 779 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
780 | fprintf (vect_dump, "unexpected misalign value"); |
781 | return false; | |
782 | } | |
783 | ||
9b14a362 | 784 | DR_MISALIGNMENT (dr) = TREE_INT_CST_LOW (misalign); |
f7064d11 | 785 | |
00518cb1 | 786 | if (vect_print_dump_info (REPORT_DETAILS)) |
86a07404 IR |
787 | { |
788 | fprintf (vect_dump, "misalign = %d bytes of ref ", DR_MISALIGNMENT (dr)); | |
789 | print_generic_expr (vect_dump, ref, TDF_SLIM); | |
790 | } | |
f7064d11 DN |
791 | |
792 | return true; | |
793 | } | |
794 | ||
795 | ||
796 | /* Function vect_compute_data_refs_alignment | |
797 | ||
798 | Compute the misalignment of data references in the loop. | |
c12cc930 | 799 | Return FALSE if a data reference is found that cannot be vectorized. */ |
f7064d11 DN |
800 | |
801 | static bool | |
802 | vect_compute_data_refs_alignment (loop_vec_info loop_vinfo) | |
803 | { | |
86a07404 | 804 | varray_type datarefs = LOOP_VINFO_DATAREFS (loop_vinfo); |
f7064d11 DN |
805 | unsigned int i; |
806 | ||
86a07404 | 807 | for (i = 0; i < VARRAY_ACTIVE_SIZE (datarefs); i++) |
f7064d11 | 808 | { |
86a07404 | 809 | struct data_reference *dr = VARRAY_GENERIC_PTR (datarefs, i); |
f7064d11 DN |
810 | if (!vect_compute_data_ref_alignment (dr)) |
811 | return false; | |
812 | } | |
813 | ||
814 | return true; | |
815 | } | |
816 | ||
817 | ||
c12cc930 KB |
818 | /* Function vect_update_misalignment_for_peel |
819 | ||
820 | DR - the data reference whose misalignment is to be adjusted. | |
821 | DR_PEEL - the data reference whose misalignment is being made | |
822 | zero in the vector loop by the peel. | |
823 | NPEEL - the number of iterations in the peel loop if the misalignment | |
824 | of DR_PEEL is known at compile time. */ | |
825 | ||
826 | static void | |
827 | vect_update_misalignment_for_peel (struct data_reference *dr, | |
828 | struct data_reference *dr_peel, int npeel) | |
829 | { | |
830 | unsigned int i; | |
831 | int drsize; | |
832 | VEC(dr_p,heap) *same_align_drs; | |
833 | struct data_reference *current_dr; | |
834 | ||
835 | if (known_alignment_for_access_p (dr) | |
836 | && DR_MISALIGNMENT (dr) == DR_MISALIGNMENT (dr_peel)) | |
837 | { | |
838 | DR_MISALIGNMENT (dr) = 0; | |
839 | return; | |
840 | } | |
841 | ||
842 | /* It can be assumed that the data refs with the same alignment as dr_peel | |
843 | are aligned in the vector loop. */ | |
844 | same_align_drs | |
845 | = STMT_VINFO_SAME_ALIGN_REFS (vinfo_for_stmt (DR_STMT (dr_peel))); | |
846 | for (i = 0; VEC_iterate (dr_p, same_align_drs, i, current_dr); i++) | |
847 | { | |
848 | if (current_dr != dr) | |
849 | continue; | |
850 | gcc_assert (DR_MISALIGNMENT (dr) == DR_MISALIGNMENT (dr_peel)); | |
851 | DR_MISALIGNMENT (dr) = 0; | |
852 | return; | |
853 | } | |
854 | ||
855 | if (known_alignment_for_access_p (dr) | |
856 | && known_alignment_for_access_p (dr_peel)) | |
857 | { | |
858 | drsize = GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dr)))); | |
859 | DR_MISALIGNMENT (dr) += npeel * drsize; | |
860 | DR_MISALIGNMENT (dr) %= UNITS_PER_SIMD_WORD; | |
861 | return; | |
862 | } | |
863 | ||
864 | DR_MISALIGNMENT (dr) = -1; | |
865 | } | |
866 | ||
867 | ||
868 | /* Function vect_verify_datarefs_alignment | |
869 | ||
870 | Return TRUE if all data references in the loop can be | |
871 | handled with respect to alignment. */ | |
872 | ||
873 | static bool | |
874 | vect_verify_datarefs_alignment (loop_vec_info loop_vinfo) | |
875 | { | |
876 | varray_type datarefs = LOOP_VINFO_DATAREFS (loop_vinfo); | |
877 | enum dr_alignment_support supportable_dr_alignment; | |
878 | unsigned int i; | |
879 | ||
880 | for (i = 0; i < VARRAY_ACTIVE_SIZE (datarefs); i++) | |
881 | { | |
882 | struct data_reference *dr = VARRAY_GENERIC_PTR (datarefs, i); | |
883 | supportable_dr_alignment = vect_supportable_dr_alignment (dr); | |
884 | if (!supportable_dr_alignment) | |
885 | { | |
886 | if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS)) | |
887 | { | |
888 | if (DR_IS_READ (dr)) | |
889 | fprintf (vect_dump, | |
890 | "not vectorized: unsupported unaligned load."); | |
891 | else | |
892 | fprintf (vect_dump, | |
893 | "not vectorized: unsupported unaligned store."); | |
894 | } | |
895 | return false; | |
896 | } | |
897 | if (supportable_dr_alignment != dr_aligned | |
898 | && vect_print_dump_info (REPORT_ALIGNMENT)) | |
899 | fprintf (vect_dump, "Vectorizing an unaligned access."); | |
900 | } | |
901 | return true; | |
902 | } | |
903 | ||
904 | ||
f7064d11 DN |
905 | /* Function vect_enhance_data_refs_alignment |
906 | ||
907 | This pass will use loop versioning and loop peeling in order to enhance | |
908 | the alignment of data references in the loop. | |
909 | ||
910 | FOR NOW: we assume that whatever versioning/peeling takes place, only the | |
911 | original loop is to be vectorized; Any other loops that are created by | |
912 | the transformations performed in this pass - are not supposed to be | |
c12cc930 KB |
913 | vectorized. This restriction will be relaxed. |
914 | ||
915 | This pass will require a cost model to guide it whether to apply peeling | |
916 | or versioning or a combination of the two. For example, the scheme that | |
917 | intel uses when given a loop with several memory accesses, is as follows: | |
918 | choose one memory access ('p') which alignment you want to force by doing | |
919 | peeling. Then, either (1) generate a loop in which 'p' is aligned and all | |
920 | other accesses are not necessarily aligned, or (2) use loop versioning to | |
921 | generate one loop in which all accesses are aligned, and another loop in | |
922 | which only 'p' is necessarily aligned. | |
923 | ||
924 | ("Automatic Intra-Register Vectorization for the Intel Architecture", | |
925 | Aart J.C. Bik, Milind Girkar, Paul M. Grey and Ximmin Tian, International | |
926 | Journal of Parallel Programming, Vol. 30, No. 2, April 2002.) | |
927 | ||
928 | Devising a cost model is the most critical aspect of this work. It will | |
929 | guide us on which access to peel for, whether to use loop versioning, how | |
930 | many versions to create, etc. The cost model will probably consist of | |
931 | generic considerations as well as target specific considerations (on | |
932 | powerpc for example, misaligned stores are more painful than misaligned | |
933 | loads). | |
934 | ||
935 | Here are the general steps involved in alignment enhancements: | |
f7064d11 | 936 | |
f7064d11 DN |
937 | -- original loop, before alignment analysis: |
938 | for (i=0; i<N; i++){ | |
939 | x = q[i]; # DR_MISALIGNMENT(q) = unknown | |
940 | p[i] = y; # DR_MISALIGNMENT(p) = unknown | |
941 | } | |
942 | ||
943 | -- After vect_compute_data_refs_alignment: | |
944 | for (i=0; i<N; i++){ | |
945 | x = q[i]; # DR_MISALIGNMENT(q) = 3 | |
946 | p[i] = y; # DR_MISALIGNMENT(p) = unknown | |
947 | } | |
948 | ||
949 | -- Possibility 1: we do loop versioning: | |
950 | if (p is aligned) { | |
951 | for (i=0; i<N; i++){ # loop 1A | |
952 | x = q[i]; # DR_MISALIGNMENT(q) = 3 | |
953 | p[i] = y; # DR_MISALIGNMENT(p) = 0 | |
954 | } | |
c12cc930 | 955 | } |
f7064d11 DN |
956 | else { |
957 | for (i=0; i<N; i++){ # loop 1B | |
958 | x = q[i]; # DR_MISALIGNMENT(q) = 3 | |
959 | p[i] = y; # DR_MISALIGNMENT(p) = unaligned | |
960 | } | |
961 | } | |
c12cc930 | 962 | |
f7064d11 DN |
963 | -- Possibility 2: we do loop peeling: |
964 | for (i = 0; i < 3; i++){ # (scalar loop, not to be vectorized). | |
965 | x = q[i]; | |
966 | p[i] = y; | |
967 | } | |
968 | for (i = 3; i < N; i++){ # loop 2A | |
969 | x = q[i]; # DR_MISALIGNMENT(q) = 0 | |
970 | p[i] = y; # DR_MISALIGNMENT(p) = unknown | |
971 | } | |
972 | ||
973 | -- Possibility 3: combination of loop peeling and versioning: | |
974 | for (i = 0; i < 3; i++){ # (scalar loop, not to be vectorized). | |
975 | x = q[i]; | |
976 | p[i] = y; | |
977 | } | |
978 | if (p is aligned) { | |
c12cc930 | 979 | for (i = 3; i<N; i++){ # loop 3A |
f7064d11 DN |
980 | x = q[i]; # DR_MISALIGNMENT(q) = 0 |
981 | p[i] = y; # DR_MISALIGNMENT(p) = 0 | |
982 | } | |
c12cc930 | 983 | } |
f7064d11 DN |
984 | else { |
985 | for (i = 3; i<N; i++){ # loop 3B | |
986 | x = q[i]; # DR_MISALIGNMENT(q) = 0 | |
987 | p[i] = y; # DR_MISALIGNMENT(p) = unaligned | |
988 | } | |
989 | } | |
990 | ||
c12cc930 KB |
991 | These loops are later passed to loop_transform to be vectorized. The |
992 | vectorizer will use the alignment information to guide the transformation | |
993 | (whether to generate regular loads/stores, or with special handling for | |
994 | misalignment). */ | |
995 | ||
996 | static bool | |
997 | vect_enhance_data_refs_alignment (loop_vec_info loop_vinfo) | |
998 | { | |
999 | varray_type datarefs = LOOP_VINFO_DATAREFS (loop_vinfo); | |
1000 | enum dr_alignment_support supportable_dr_alignment; | |
1001 | struct data_reference *dr0 = NULL; | |
1002 | struct data_reference *dr; | |
1003 | unsigned int i; | |
1004 | bool do_peeling = false; | |
1005 | bool do_versioning = false; | |
1006 | bool stat; | |
1007 | ||
1008 | /* While cost model enhancements are expected in the future, the high level | |
1009 | view of the code at this time is as follows: | |
1010 | ||
1011 | A) If there is a misaligned write then see if peeling to align this write | |
1012 | can make all data references satisfy vect_supportable_dr_alignment. | |
1013 | If so, update data structures as needed and return true. Note that | |
1014 | at this time vect_supportable_dr_alignment is known to return false | |
1015 | for a a misaligned write. | |
1016 | ||
1017 | B) If peeling wasn't possible and there is a data reference with an | |
1018 | unknown misalignment that does not satisfy vect_supportable_dr_alignment | |
1019 | then see if loop versioning checks can be used to make all data | |
1020 | references satisfy vect_supportable_dr_alignment. If so, update | |
1021 | data structures as needed and return true. | |
1022 | ||
1023 | C) If neither peeling nor versioning were successful then return false if | |
1024 | any data reference does not satisfy vect_supportable_dr_alignment. | |
1025 | ||
1026 | D) Return true (all data references satisfy vect_supportable_dr_alignment). | |
1027 | ||
1028 | Note, Possibility 3 above (which is peeling and versioning together) is not | |
1029 | being done at this time. */ | |
f7064d11 DN |
1030 | |
1031 | /* (1) Peeling to force alignment. */ | |
1032 | ||
1033 | /* (1.1) Decide whether to perform peeling, and how many iterations to peel: | |
1034 | Considerations: | |
1035 | + How many accesses will become aligned due to the peeling | |
1036 | - How many accesses will become unaligned due to the peeling, | |
1037 | and the cost of misaligned accesses. | |
1038 | - The cost of peeling (the extra runtime checks, the increase | |
1039 | in code size). | |
1040 | ||
1041 | The scheme we use FORNOW: peel to force the alignment of the first | |
1042 | misaligned store in the loop. | |
1043 | Rationale: misaligned stores are not yet supported. | |
1044 | ||
c12cc930 | 1045 | TODO: Use a cost model. */ |
f7064d11 | 1046 | |
c12cc930 | 1047 | for (i = 0; i < VARRAY_ACTIVE_SIZE (datarefs); i++) |
f7064d11 | 1048 | { |
c12cc930 KB |
1049 | dr = VARRAY_GENERIC_PTR (datarefs, i); |
1050 | if (!DR_IS_READ (dr) && !aligned_access_p (dr)) | |
1051 | { | |
1052 | dr0 = dr; | |
1053 | do_peeling = true; | |
1054 | break; | |
1055 | } | |
f7064d11 DN |
1056 | } |
1057 | ||
c12cc930 KB |
1058 | /* Often peeling for alignment will require peeling for loop-bound, which in |
1059 | turn requires that we know how to adjust the loop ivs after the loop. */ | |
1060 | if (!vect_can_advance_ivs_p (loop_vinfo)) | |
1061 | do_peeling = false; | |
f7064d11 | 1062 | |
c12cc930 | 1063 | if (do_peeling) |
f7064d11 | 1064 | { |
5f55a1ba DN |
1065 | int mis; |
1066 | int npeel = 0; | |
1067 | ||
1068 | if (known_alignment_for_access_p (dr0)) | |
c12cc930 KB |
1069 | { |
1070 | /* Since it's known at compile time, compute the number of iterations | |
1071 | in the peeled loop (the peeling factor) for use in updating | |
1072 | DR_MISALIGNMENT values. The peeling factor is the vectorization | |
1073 | factor minus the misalignment as an element count. */ | |
1074 | mis = DR_MISALIGNMENT (dr0); | |
1075 | mis /= GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dr0)))); | |
1076 | npeel = LOOP_VINFO_VECT_FACTOR (loop_vinfo) - mis; | |
1077 | } | |
1078 | ||
1079 | /* Ensure that all data refs can be vectorized after the peel. */ | |
1080 | for (i = 0; i < VARRAY_ACTIVE_SIZE (datarefs); i++) | |
1081 | { | |
1082 | int save_misalignment; | |
1083 | ||
1084 | dr = VARRAY_GENERIC_PTR (datarefs, i); | |
1085 | if (dr == dr0) | |
1086 | continue; | |
1087 | save_misalignment = DR_MISALIGNMENT (dr); | |
1088 | vect_update_misalignment_for_peel (dr, dr0, npeel); | |
1089 | supportable_dr_alignment = vect_supportable_dr_alignment (dr); | |
1090 | DR_MISALIGNMENT (dr) = save_misalignment; | |
1091 | ||
1092 | if (!supportable_dr_alignment) | |
1093 | { | |
1094 | do_peeling = false; | |
1095 | break; | |
1096 | } | |
f7064d11 | 1097 | } |
5f55a1ba | 1098 | |
c12cc930 KB |
1099 | if (do_peeling) |
1100 | { | |
1101 | /* (1.2) Update the DR_MISALIGNMENT of each data reference DR_i. | |
1102 | If the misalignment of DR_i is identical to that of dr0 then set | |
1103 | DR_MISALIGNMENT (DR_i) to zero. If the misalignment of DR_i and | |
1104 | dr0 are known at compile time then increment DR_MISALIGNMENT (DR_i) | |
1105 | by the peeling factor times the element size of DR_i (MOD the | |
1106 | vectorization factor times the size). Otherwise, the | |
1107 | misalignment of DR_i must be set to unknown. */ | |
5f55a1ba DN |
1108 | for (i = 0; i < VARRAY_ACTIVE_SIZE (datarefs); i++) |
1109 | { | |
c12cc930 KB |
1110 | dr = VARRAY_GENERIC_PTR (datarefs, i); |
1111 | if (dr == dr0) | |
1112 | continue; | |
1113 | vect_update_misalignment_for_peel (dr, dr0, npeel); | |
5f55a1ba | 1114 | } |
5f55a1ba | 1115 | |
c12cc930 KB |
1116 | LOOP_VINFO_UNALIGNED_DR (loop_vinfo) = dr0; |
1117 | LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo) = DR_MISALIGNMENT (dr0); | |
1118 | DR_MISALIGNMENT (dr0) = 0; | |
1119 | if (vect_print_dump_info (REPORT_ALIGNMENT)) | |
1120 | fprintf (vect_dump, "Alignment of access forced using peeling."); | |
1121 | ||
1122 | if (vect_print_dump_info (REPORT_DETAILS)) | |
1123 | fprintf (vect_dump, "Peeling for alignment will be applied."); | |
1124 | ||
1125 | stat = vect_verify_datarefs_alignment (loop_vinfo); | |
1126 | gcc_assert (stat); | |
1127 | return stat; | |
1128 | } | |
1129 | } | |
1130 | ||
1131 | ||
1132 | /* (2) Versioning to force alignment. */ | |
1133 | ||
1134 | /* Try versioning if: | |
1135 | 1) flag_tree_vect_loop_version is TRUE | |
1136 | 2) optimize_size is FALSE | |
1137 | 3) there is at least one unsupported misaligned data ref with an unknown | |
1138 | misalignment, and | |
1139 | 4) all misaligned data refs with a known misalignment are supported, and | |
1140 | 5) the number of runtime alignment checks is within reason. */ | |
1141 | ||
1142 | do_versioning = flag_tree_vect_loop_version && (!optimize_size); | |
1143 | ||
1144 | if (do_versioning) | |
1145 | { | |
1146 | for (i = 0; i < VARRAY_ACTIVE_SIZE (datarefs); i++) | |
bb748329 | 1147 | { |
c12cc930 KB |
1148 | dr = VARRAY_GENERIC_PTR (datarefs, i); |
1149 | ||
1150 | if (aligned_access_p (dr)) | |
1151 | continue; | |
1152 | ||
1153 | supportable_dr_alignment = vect_supportable_dr_alignment (dr); | |
1154 | ||
1155 | if (!supportable_dr_alignment) | |
1156 | { | |
1157 | tree stmt; | |
1158 | int mask; | |
1159 | tree vectype; | |
1160 | ||
1161 | if (known_alignment_for_access_p (dr) | |
1162 | || VEC_length (tree, | |
1163 | LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo)) | |
1164 | >= (unsigned) PARAM_VALUE (PARAM_VECT_MAX_VERSION_CHECKS)) | |
1165 | { | |
1166 | do_versioning = false; | |
1167 | break; | |
1168 | } | |
1169 | ||
1170 | stmt = DR_STMT (dr); | |
1171 | vectype = STMT_VINFO_VECTYPE (vinfo_for_stmt (stmt)); | |
1172 | gcc_assert (vectype); | |
1173 | ||
1174 | /* The rightmost bits of an aligned address must be zeros. | |
1175 | Construct the mask needed for this test. For example, | |
1176 | GET_MODE_SIZE for the vector mode V4SI is 16 bytes so the | |
1177 | mask must be 15 = 0xf. */ | |
1178 | mask = GET_MODE_SIZE (TYPE_MODE (vectype)) - 1; | |
1179 | ||
1180 | /* FORNOW: use the same mask to test all potentially unaligned | |
1181 | references in the loop. The vectorizer currently supports | |
1182 | a single vector size, see the reference to | |
1183 | GET_MODE_NUNITS (TYPE_MODE (vectype)) where the | |
1184 | vectorization factor is computed. */ | |
1185 | gcc_assert (!LOOP_VINFO_PTR_MASK (loop_vinfo) | |
1186 | || LOOP_VINFO_PTR_MASK (loop_vinfo) == mask); | |
1187 | LOOP_VINFO_PTR_MASK (loop_vinfo) = mask; | |
1188 | VEC_safe_push (tree, heap, | |
1189 | LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo), | |
1190 | DR_STMT (dr)); | |
1191 | } | |
1192 | } | |
1193 | ||
1194 | /* Versioning requires at least one misaligned data reference. */ | |
1195 | if (VEC_length (tree, LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo)) == 0) | |
1196 | do_versioning = false; | |
1197 | else if (!do_versioning) | |
1198 | VEC_truncate (tree, LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo), 0); | |
1199 | } | |
1200 | ||
1201 | if (do_versioning) | |
1202 | { | |
1203 | VEC(tree,heap) *may_misalign_stmts | |
1204 | = LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo); | |
1205 | tree stmt; | |
1206 | ||
1207 | /* It can now be assumed that the data references in the statements | |
1208 | in LOOP_VINFO_MAY_MISALIGN_STMTS will be aligned in the version | |
1209 | of the loop being vectorized. */ | |
1210 | for (i = 0; VEC_iterate (tree, may_misalign_stmts, i, stmt); i++) | |
1211 | { | |
1212 | stmt_vec_info stmt_info = vinfo_for_stmt (stmt); | |
1213 | dr = STMT_VINFO_DATA_REF (stmt_info); | |
bb748329 | 1214 | DR_MISALIGNMENT (dr) = 0; |
c12cc930 KB |
1215 | if (vect_print_dump_info (REPORT_ALIGNMENT)) |
1216 | fprintf (vect_dump, "Alignment of access forced using versioning."); | |
bb748329 DN |
1217 | } |
1218 | ||
c12cc930 KB |
1219 | if (vect_print_dump_info (REPORT_DETAILS)) |
1220 | fprintf (vect_dump, "Versioning for alignment will be applied."); | |
1221 | ||
1222 | /* Peeling and versioning can't be done together at this time. */ | |
1223 | gcc_assert (! (do_peeling && do_versioning)); | |
1224 | ||
1225 | stat = vect_verify_datarefs_alignment (loop_vinfo); | |
1226 | gcc_assert (stat); | |
1227 | return stat; | |
f7064d11 | 1228 | } |
c12cc930 KB |
1229 | |
1230 | /* This point is reached if neither peeling nor versioning is being done. */ | |
1231 | gcc_assert (! (do_peeling || do_versioning)); | |
1232 | ||
1233 | stat = vect_verify_datarefs_alignment (loop_vinfo); | |
1234 | return stat; | |
f7064d11 DN |
1235 | } |
1236 | ||
1237 | ||
1238 | /* Function vect_analyze_data_refs_alignment | |
1239 | ||
1240 | Analyze the alignment of the data-references in the loop. | |
c12cc930 | 1241 | Return FALSE if a data reference is found that cannot be vectorized. */ |
f7064d11 DN |
1242 | |
1243 | static bool | |
1244 | vect_analyze_data_refs_alignment (loop_vec_info loop_vinfo) | |
1245 | { | |
00518cb1 | 1246 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
1247 | fprintf (vect_dump, "=== vect_analyze_data_refs_alignment ==="); |
1248 | ||
f7064d11 DN |
1249 | if (!vect_compute_data_refs_alignment (loop_vinfo)) |
1250 | { | |
00518cb1 | 1251 | if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS)) |
f7064d11 DN |
1252 | fprintf (vect_dump, |
1253 | "not vectorized: can't calculate alignment for data ref."); | |
1254 | return false; | |
1255 | } | |
1256 | ||
f7064d11 DN |
1257 | return true; |
1258 | } | |
1259 | ||
1260 | ||
1261 | /* Function vect_analyze_data_ref_access. | |
1262 | ||
1263 | Analyze the access pattern of the data-reference DR. For now, a data access | |
c12cc930 | 1264 | has to be consecutive to be considered vectorizable. */ |
f7064d11 DN |
1265 | |
1266 | static bool | |
1267 | vect_analyze_data_ref_access (struct data_reference *dr) | |
1268 | { | |
86a07404 | 1269 | tree step = DR_STEP (dr); |
f7064d11 DN |
1270 | tree scalar_type = TREE_TYPE (DR_REF (dr)); |
1271 | ||
1272 | if (!step || tree_int_cst_compare (step, TYPE_SIZE_UNIT (scalar_type))) | |
1273 | { | |
00518cb1 | 1274 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
1275 | fprintf (vect_dump, "not consecutive access"); |
1276 | return false; | |
1277 | } | |
1278 | return true; | |
1279 | } | |
1280 | ||
1281 | ||
1282 | /* Function vect_analyze_data_ref_accesses. | |
1283 | ||
1284 | Analyze the access pattern of all the data references in the loop. | |
1285 | ||
1286 | FORNOW: the only access pattern that is considered vectorizable is a | |
1287 | simple step 1 (consecutive) access. | |
1288 | ||
1289 | FORNOW: handle only arrays and pointer accesses. */ | |
1290 | ||
1291 | static bool | |
1292 | vect_analyze_data_ref_accesses (loop_vec_info loop_vinfo) | |
1293 | { | |
1294 | unsigned int i; | |
86a07404 | 1295 | varray_type datarefs = LOOP_VINFO_DATAREFS (loop_vinfo); |
f7064d11 | 1296 | |
00518cb1 | 1297 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
1298 | fprintf (vect_dump, "=== vect_analyze_data_ref_accesses ==="); |
1299 | ||
86a07404 | 1300 | for (i = 0; i < VARRAY_ACTIVE_SIZE (datarefs); i++) |
f7064d11 | 1301 | { |
86a07404 IR |
1302 | struct data_reference *dr = VARRAY_GENERIC_PTR (datarefs, i); |
1303 | if (!vect_analyze_data_ref_access (dr)) | |
f7064d11 | 1304 | { |
00518cb1 | 1305 | if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS)) |
f7064d11 DN |
1306 | fprintf (vect_dump, "not vectorized: complicated access pattern."); |
1307 | return false; | |
1308 | } | |
1309 | } | |
1310 | ||
1311 | return true; | |
1312 | } | |
1313 | ||
1314 | ||
f7064d11 DN |
1315 | /* Function vect_analyze_data_refs. |
1316 | ||
86a07404 | 1317 | Find all the data references in the loop. |
f7064d11 | 1318 | |
86a07404 | 1319 | The general structure of the analysis of data refs in the vectorizer is as |
f7064d11 | 1320 | follows: |
86a07404 IR |
1321 | 1- vect_analyze_data_refs(loop): call compute_data_dependences_for_loop to |
1322 | find and analyze all data-refs in the loop and their dependences. | |
1323 | 2- vect_analyze_dependences(): apply dependence testing using ddrs. | |
f7064d11 DN |
1324 | 3- vect_analyze_drs_alignment(): check that ref_stmt.alignment is ok. |
1325 | 4- vect_analyze_drs_access(): check that ref_stmt.step is ok. | |
1326 | ||
86a07404 | 1327 | */ |
f7064d11 DN |
1328 | |
1329 | static bool | |
86a07404 | 1330 | vect_analyze_data_refs (loop_vec_info loop_vinfo) |
f7064d11 DN |
1331 | { |
1332 | struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); | |
86a07404 IR |
1333 | unsigned int i; |
1334 | varray_type datarefs; | |
1335 | tree scalar_type; | |
f7064d11 | 1336 | |
00518cb1 | 1337 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
1338 | fprintf (vect_dump, "=== vect_analyze_data_refs ==="); |
1339 | ||
86a07404 IR |
1340 | compute_data_dependences_for_loop (loop, false, |
1341 | &(LOOP_VINFO_DATAREFS (loop_vinfo)), | |
1342 | &(LOOP_VINFO_DDRS (loop_vinfo))); | |
f7064d11 | 1343 | |
86a07404 IR |
1344 | /* Go through the data-refs, check that the analysis succeeded. Update pointer |
1345 | from stmt_vec_info struct to DR and vectype. */ | |
1346 | datarefs = LOOP_VINFO_DATAREFS (loop_vinfo); | |
1347 | for (i = 0; i < VARRAY_ACTIVE_SIZE (datarefs); i++) | |
1348 | { | |
1349 | struct data_reference *dr = VARRAY_GENERIC_PTR (datarefs, i); | |
1350 | tree stmt; | |
1351 | stmt_vec_info stmt_info; | |
1352 | ||
1353 | if (!dr || !DR_REF (dr)) | |
1354 | { | |
1355 | if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS)) | |
d7770457 | 1356 | fprintf (vect_dump, "not vectorized: unhandled data-ref "); |
86a07404 IR |
1357 | return false; |
1358 | } | |
1359 | ||
1360 | /* Update DR field in stmt_vec_info struct. */ | |
1361 | stmt = DR_STMT (dr); | |
1362 | stmt_info = vinfo_for_stmt (stmt); | |
1363 | ||
1364 | if (STMT_VINFO_DATA_REF (stmt_info)) | |
1365 | { | |
1366 | if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS)) | |
1367 | { | |
1368 | fprintf (vect_dump, | |
1369 | "not vectorized: more than one data ref in stmt: "); | |
1370 | print_generic_expr (vect_dump, stmt, TDF_SLIM); | |
1371 | } | |
1372 | return false; | |
1373 | } | |
1374 | STMT_VINFO_DATA_REF (stmt_info) = dr; | |
1375 | ||
1376 | /* Check that analysis of the data-ref succeeded. */ | |
1377 | if (!DR_BASE_ADDRESS (dr) || !DR_OFFSET (dr) || !DR_INIT (dr) | |
1378 | || !DR_STEP (dr)) | |
1379 | { | |
1380 | if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS)) | |
1381 | { | |
1382 | fprintf (vect_dump, "not vectorized: data ref analysis failed "); | |
1383 | print_generic_expr (vect_dump, stmt, TDF_SLIM); | |
1384 | } | |
1385 | return false; | |
1386 | } | |
1387 | if (!DR_MEMTAG (dr)) | |
1388 | { | |
1389 | if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS)) | |
1390 | { | |
1391 | fprintf (vect_dump, "not vectorized: no memory tag for "); | |
1392 | print_generic_expr (vect_dump, DR_REF (dr), TDF_SLIM); | |
1393 | } | |
1394 | return false; | |
1395 | } | |
1396 | ||
1397 | /* Set vectype for STMT. */ | |
1398 | scalar_type = TREE_TYPE (DR_REF (dr)); | |
1399 | STMT_VINFO_VECTYPE (stmt_info) = | |
1400 | get_vectype_for_scalar_type (scalar_type); | |
1401 | if (!STMT_VINFO_VECTYPE (stmt_info)) | |
1402 | { | |
1403 | if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS)) | |
1404 | { | |
1405 | fprintf (vect_dump, | |
1406 | "not vectorized: no vectype for stmt: "); | |
1407 | print_generic_expr (vect_dump, stmt, TDF_SLIM); | |
1408 | fprintf (vect_dump, " scalar_type: "); | |
1409 | print_generic_expr (vect_dump, scalar_type, TDF_DETAILS); | |
1410 | } | |
1411 | return false; | |
1412 | } | |
f7064d11 | 1413 | } |
86a07404 | 1414 | |
f7064d11 DN |
1415 | return true; |
1416 | } | |
1417 | ||
1418 | ||
1419 | /* Utility functions used by vect_mark_stmts_to_be_vectorized. */ | |
1420 | ||
1421 | /* Function vect_mark_relevant. | |
1422 | ||
1423 | Mark STMT as "relevant for vectorization" and add it to WORKLIST. */ | |
1424 | ||
1425 | static void | |
88088c03 DN |
1426 | vect_mark_relevant (VEC(tree,heap) **worklist, tree stmt, |
1427 | bool relevant_p, bool live_p) | |
f7064d11 | 1428 | { |
88088c03 DN |
1429 | stmt_vec_info stmt_info = vinfo_for_stmt (stmt); |
1430 | bool save_relevant_p = STMT_VINFO_RELEVANT_P (stmt_info); | |
1431 | bool save_live_p = STMT_VINFO_LIVE_P (stmt_info); | |
f7064d11 | 1432 | |
00518cb1 | 1433 | if (vect_print_dump_info (REPORT_DETAILS)) |
88088c03 | 1434 | fprintf (vect_dump, "mark relevant %d, live %d.",relevant_p, live_p); |
f7064d11 | 1435 | |
88088c03 | 1436 | STMT_VINFO_LIVE_P (stmt_info) |= live_p; |
61d3cdbb | 1437 | STMT_VINFO_RELEVANT_P (stmt_info) |= relevant_p; |
f7064d11 | 1438 | |
88088c03 | 1439 | if (TREE_CODE (stmt) == PHI_NODE) |
61d3cdbb DN |
1440 | /* Don't put phi-nodes in the worklist. Phis that are marked relevant |
1441 | or live will fail vectorization later on. */ | |
88088c03 | 1442 | return; |
f7064d11 | 1443 | |
88088c03 DN |
1444 | if (STMT_VINFO_RELEVANT_P (stmt_info) == save_relevant_p |
1445 | && STMT_VINFO_LIVE_P (stmt_info) == save_live_p) | |
f7064d11 | 1446 | { |
00518cb1 | 1447 | if (vect_print_dump_info (REPORT_DETAILS)) |
88088c03 | 1448 | fprintf (vect_dump, "already marked relevant/live."); |
f7064d11 DN |
1449 | return; |
1450 | } | |
1451 | ||
51d00891 | 1452 | VEC_safe_push (tree, heap, *worklist, stmt); |
f7064d11 DN |
1453 | } |
1454 | ||
1455 | ||
1456 | /* Function vect_stmt_relevant_p. | |
1457 | ||
1458 | Return true if STMT in loop that is represented by LOOP_VINFO is | |
1459 | "relevant for vectorization". | |
1460 | ||
1461 | A stmt is considered "relevant for vectorization" if: | |
1462 | - it has uses outside the loop. | |
1463 | - it has vdefs (it alters memory). | |
1464 | - control stmts in the loop (except for the exit condition). | |
1465 | ||
1466 | CHECKME: what other side effects would the vectorizer allow? */ | |
1467 | ||
1468 | static bool | |
88088c03 DN |
1469 | vect_stmt_relevant_p (tree stmt, loop_vec_info loop_vinfo, |
1470 | bool *relevant_p, bool *live_p) | |
f7064d11 | 1471 | { |
f7064d11 | 1472 | struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); |
f430bae8 AM |
1473 | ssa_op_iter op_iter; |
1474 | imm_use_iterator imm_iter; | |
1475 | use_operand_p use_p; | |
f47c96aa | 1476 | def_operand_p def_p; |
f7064d11 | 1477 | |
88088c03 DN |
1478 | *relevant_p = false; |
1479 | *live_p = false; | |
1480 | ||
f7064d11 DN |
1481 | /* cond stmt other than loop exit cond. */ |
1482 | if (is_ctrl_stmt (stmt) && (stmt != LOOP_VINFO_EXIT_COND (loop_vinfo))) | |
88088c03 | 1483 | *relevant_p = true; |
f7064d11 DN |
1484 | |
1485 | /* changing memory. */ | |
f47c96aa AM |
1486 | if (TREE_CODE (stmt) != PHI_NODE) |
1487 | if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_VIRTUAL_DEFS)) | |
1488 | { | |
00518cb1 | 1489 | if (vect_print_dump_info (REPORT_DETAILS)) |
f47c96aa | 1490 | fprintf (vect_dump, "vec_stmt_relevant_p: stmt has vdefs."); |
88088c03 | 1491 | *relevant_p = true; |
f47c96aa | 1492 | } |
f7064d11 DN |
1493 | |
1494 | /* uses outside the loop. */ | |
f47c96aa | 1495 | FOR_EACH_PHI_OR_STMT_DEF (def_p, stmt, op_iter, SSA_OP_DEF) |
f7064d11 | 1496 | { |
f47c96aa | 1497 | FOR_EACH_IMM_USE_FAST (use_p, imm_iter, DEF_FROM_PTR (def_p)) |
f7064d11 | 1498 | { |
f430bae8 AM |
1499 | basic_block bb = bb_for_stmt (USE_STMT (use_p)); |
1500 | if (!flow_bb_inside_loop_p (loop, bb)) | |
1501 | { | |
00518cb1 | 1502 | if (vect_print_dump_info (REPORT_DETAILS)) |
f430bae8 | 1503 | fprintf (vect_dump, "vec_stmt_relevant_p: used out of loop."); |
88088c03 DN |
1504 | |
1505 | /* We expect all such uses to be in the loop exit phis | |
1506 | (because of loop closed form) */ | |
1507 | gcc_assert (TREE_CODE (USE_STMT (use_p)) == PHI_NODE); | |
1508 | gcc_assert (bb == loop->single_exit->dest); | |
1509 | ||
1510 | *live_p = true; | |
f430bae8 | 1511 | } |
f7064d11 DN |
1512 | } |
1513 | } | |
1514 | ||
88088c03 | 1515 | return (*live_p || *relevant_p); |
f7064d11 DN |
1516 | } |
1517 | ||
1518 | ||
1519 | /* Function vect_mark_stmts_to_be_vectorized. | |
1520 | ||
1521 | Not all stmts in the loop need to be vectorized. For example: | |
1522 | ||
1523 | for i... | |
1524 | for j... | |
1525 | 1. T0 = i + j | |
1526 | 2. T1 = a[T0] | |
1527 | ||
1528 | 3. j = j + 1 | |
1529 | ||
1530 | Stmt 1 and 3 do not need to be vectorized, because loop control and | |
1531 | addressing of vectorized data-refs are handled differently. | |
1532 | ||
1533 | This pass detects such stmts. */ | |
1534 | ||
1535 | static bool | |
1536 | vect_mark_stmts_to_be_vectorized (loop_vec_info loop_vinfo) | |
1537 | { | |
51d00891 | 1538 | VEC(tree,heap) *worklist; |
f7064d11 DN |
1539 | struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); |
1540 | basic_block *bbs = LOOP_VINFO_BBS (loop_vinfo); | |
1541 | unsigned int nbbs = loop->num_nodes; | |
1542 | block_stmt_iterator si; | |
f47c96aa | 1543 | tree stmt, use; |
88088c03 | 1544 | stmt_ann_t ann; |
f47c96aa | 1545 | ssa_op_iter iter; |
f7064d11 | 1546 | unsigned int i; |
88088c03 | 1547 | stmt_vec_info stmt_vinfo; |
f7064d11 DN |
1548 | basic_block bb; |
1549 | tree phi; | |
88088c03 DN |
1550 | bool relevant_p, live_p; |
1551 | tree def, def_stmt; | |
1552 | enum vect_def_type dt; | |
f7064d11 | 1553 | |
00518cb1 | 1554 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
1555 | fprintf (vect_dump, "=== vect_mark_stmts_to_be_vectorized ==="); |
1556 | ||
88088c03 DN |
1557 | worklist = VEC_alloc (tree, heap, 64); |
1558 | ||
1559 | /* 1. Init worklist. */ | |
1560 | ||
f7064d11 DN |
1561 | bb = loop->header; |
1562 | for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) | |
1563 | { | |
00518cb1 | 1564 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
1565 | { |
1566 | fprintf (vect_dump, "init: phi relevant? "); | |
1567 | print_generic_expr (vect_dump, phi, TDF_SLIM); | |
1568 | } | |
1569 | ||
88088c03 DN |
1570 | if (vect_stmt_relevant_p (phi, loop_vinfo, &relevant_p, &live_p)) |
1571 | vect_mark_relevant (&worklist, phi, relevant_p, live_p); | |
f7064d11 DN |
1572 | } |
1573 | ||
f7064d11 DN |
1574 | for (i = 0; i < nbbs; i++) |
1575 | { | |
1576 | bb = bbs[i]; | |
1577 | for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si)) | |
1578 | { | |
1579 | stmt = bsi_stmt (si); | |
1580 | ||
00518cb1 | 1581 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
1582 | { |
1583 | fprintf (vect_dump, "init: stmt relevant? "); | |
1584 | print_generic_expr (vect_dump, stmt, TDF_SLIM); | |
1585 | } | |
1586 | ||
88088c03 DN |
1587 | if (vect_stmt_relevant_p (stmt, loop_vinfo, &relevant_p, &live_p)) |
1588 | vect_mark_relevant (&worklist, stmt, relevant_p, live_p); | |
f7064d11 DN |
1589 | } |
1590 | } | |
1591 | ||
1592 | ||
1593 | /* 2. Process_worklist */ | |
1594 | ||
51d00891 | 1595 | while (VEC_length (tree, worklist) > 0) |
f7064d11 | 1596 | { |
51d00891 | 1597 | stmt = VEC_pop (tree, worklist); |
f7064d11 | 1598 | |
00518cb1 | 1599 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
1600 | { |
1601 | fprintf (vect_dump, "worklist: examine stmt: "); | |
1602 | print_generic_expr (vect_dump, stmt, TDF_SLIM); | |
1603 | } | |
1604 | ||
88088c03 DN |
1605 | /* Examine the USEs of STMT. For each ssa-name USE thta is defined |
1606 | in the loop, mark the stmt that defines it (DEF_STMT) as | |
1607 | relevant/irrelevant and live/dead according to the liveness and | |
1608 | relevance properties of STMT. | |
1609 | */ | |
f7064d11 | 1610 | |
88088c03 | 1611 | gcc_assert (TREE_CODE (stmt) != PHI_NODE); |
f7064d11 | 1612 | |
88088c03 DN |
1613 | ann = stmt_ann (stmt); |
1614 | stmt_vinfo = vinfo_for_stmt (stmt); | |
f7064d11 | 1615 | |
88088c03 DN |
1616 | relevant_p = STMT_VINFO_RELEVANT_P (stmt_vinfo); |
1617 | live_p = STMT_VINFO_LIVE_P (stmt_vinfo); | |
1618 | ||
1619 | /* Generally, the liveness and relevance properties of STMT are | |
1620 | propagated to the DEF_STMTs of its USEs: | |
1621 | STMT_VINFO_LIVE_P (DEF_STMT_info) <-- live_p | |
1622 | STMT_VINFO_RELEVANT_P (DEF_STMT_info) <-- relevant_p | |
1623 | ||
1624 | Exceptions: | |
1625 | ||
61d3cdbb DN |
1626 | (case 1) |
1627 | If USE is used only for address computations (e.g. array indexing), | |
88088c03 DN |
1628 | which does not need to be directly vectorized, then the |
1629 | liveness/relevance of the respective DEF_STMT is left unchanged. | |
1630 | ||
61d3cdbb DN |
1631 | (case 2) |
1632 | If STMT has been identified as defining a reduction variable, then | |
1633 | we have two cases: | |
1634 | (case 2.1) | |
1635 | The last use of STMT is the reduction-variable, which is defined | |
1636 | by a loop-header-phi. We don't want to mark the phi as live or | |
1637 | relevant (because it does not need to be vectorized, it is handled | |
1638 | as part of the vectorization of the reduction), so in this case we | |
1639 | skip the call to vect_mark_relevant. | |
1640 | (case 2.2) | |
1641 | The rest of the uses of STMT are defined in the loop body. For | |
1642 | the def_stmt of these uses we want to set liveness/relevance | |
1643 | as follows: | |
1644 | STMT_VINFO_LIVE_P (DEF_STMT_info) <-- false | |
1645 | STMT_VINFO_RELEVANT_P (DEF_STMT_info) <-- true | |
1646 | because even though STMT is classified as live (since it defines a | |
1647 | value that is used across loop iterations) and irrelevant (since it | |
1648 | is not used inside the loop), it will be vectorized, and therefore | |
1649 | the corresponding DEF_STMTs need to marked as relevant. | |
88088c03 DN |
1650 | */ |
1651 | ||
61d3cdbb | 1652 | /* case 2.2: */ |
88088c03 DN |
1653 | if (STMT_VINFO_DEF_TYPE (stmt_vinfo) == vect_reduction_def) |
1654 | { | |
1655 | gcc_assert (!relevant_p && live_p); | |
1656 | relevant_p = true; | |
1657 | live_p = false; | |
1658 | } | |
f7064d11 | 1659 | |
f47c96aa | 1660 | FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE) |
f7064d11 | 1661 | { |
61d3cdbb DN |
1662 | /* case 1: we are only interested in uses that need to be vectorized. |
1663 | Uses that are used for address computation are not considered | |
1664 | relevant. | |
f7064d11 | 1665 | */ |
61d3cdbb DN |
1666 | if (!exist_non_indexing_operands_for_use_p (use, stmt)) |
1667 | continue; | |
f7064d11 | 1668 | |
61d3cdbb DN |
1669 | if (!vect_is_simple_use (use, loop_vinfo, &def_stmt, &def, &dt)) |
1670 | { | |
00518cb1 | 1671 | if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS)) |
61d3cdbb DN |
1672 | fprintf (vect_dump, "not vectorized: unsupported use in stmt."); |
1673 | VEC_free (tree, heap, worklist); | |
1674 | return false; | |
1675 | } | |
f7064d11 | 1676 | |
61d3cdbb DN |
1677 | if (!def_stmt || IS_EMPTY_STMT (def_stmt)) |
1678 | continue; | |
f7064d11 | 1679 | |
00518cb1 | 1680 | if (vect_print_dump_info (REPORT_DETAILS)) |
61d3cdbb DN |
1681 | { |
1682 | fprintf (vect_dump, "worklist: examine use %d: ", i); | |
1683 | print_generic_expr (vect_dump, use, TDF_SLIM); | |
1684 | } | |
88088c03 | 1685 | |
61d3cdbb DN |
1686 | bb = bb_for_stmt (def_stmt); |
1687 | if (!flow_bb_inside_loop_p (loop, bb)) | |
1688 | continue; | |
88088c03 | 1689 | |
61d3cdbb DN |
1690 | /* case 2.1: the reduction-use does not mark the defining-phi |
1691 | as relevant. */ | |
1692 | if (STMT_VINFO_DEF_TYPE (stmt_vinfo) == vect_reduction_def | |
1693 | && TREE_CODE (def_stmt) == PHI_NODE) | |
1694 | continue; | |
1695 | ||
1696 | vect_mark_relevant (&worklist, def_stmt, relevant_p, live_p); | |
f7064d11 DN |
1697 | } |
1698 | } /* while worklist */ | |
1699 | ||
51d00891 | 1700 | VEC_free (tree, heap, worklist); |
f7064d11 DN |
1701 | return true; |
1702 | } | |
1703 | ||
1704 | ||
1705 | /* Function vect_can_advance_ivs_p | |
1706 | ||
c12cc930 | 1707 | In case the number of iterations that LOOP iterates is unknown at compile |
f7064d11 DN |
1708 | time, an epilog loop will be generated, and the loop induction variables |
1709 | (IVs) will be "advanced" to the value they are supposed to take just before | |
1710 | the epilog loop. Here we check that the access function of the loop IVs | |
1711 | and the expression that represents the loop bound are simple enough. | |
1712 | These restrictions will be relaxed in the future. */ | |
1713 | ||
1714 | static bool | |
1715 | vect_can_advance_ivs_p (loop_vec_info loop_vinfo) | |
1716 | { | |
1717 | struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); | |
1718 | basic_block bb = loop->header; | |
1719 | tree phi; | |
1720 | ||
1721 | /* Analyze phi functions of the loop header. */ | |
1722 | ||
00518cb1 | 1723 | if (vect_print_dump_info (REPORT_DETAILS)) |
88088c03 DN |
1724 | fprintf (vect_dump, "=== vect_can_advance_ivs_p ==="); |
1725 | ||
f7064d11 DN |
1726 | for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) |
1727 | { | |
1728 | tree access_fn = NULL; | |
1729 | tree evolution_part; | |
1730 | ||
00518cb1 | 1731 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
1732 | { |
1733 | fprintf (vect_dump, "Analyze phi: "); | |
1734 | print_generic_expr (vect_dump, phi, TDF_SLIM); | |
1735 | } | |
1736 | ||
1737 | /* Skip virtual phi's. The data dependences that are associated with | |
1738 | virtual defs/uses (i.e., memory accesses) are analyzed elsewhere. */ | |
1739 | ||
1740 | if (!is_gimple_reg (SSA_NAME_VAR (PHI_RESULT (phi)))) | |
1741 | { | |
00518cb1 | 1742 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
1743 | fprintf (vect_dump, "virtual phi. skip."); |
1744 | continue; | |
1745 | } | |
1746 | ||
61d3cdbb DN |
1747 | /* Skip reduction phis. */ |
1748 | ||
1749 | if (STMT_VINFO_DEF_TYPE (vinfo_for_stmt (phi)) == vect_reduction_def) | |
1750 | { | |
00518cb1 | 1751 | if (vect_print_dump_info (REPORT_DETAILS)) |
61d3cdbb DN |
1752 | fprintf (vect_dump, "reduc phi. skip."); |
1753 | continue; | |
1754 | } | |
1755 | ||
f7064d11 DN |
1756 | /* Analyze the evolution function. */ |
1757 | ||
1758 | access_fn = instantiate_parameters | |
1759 | (loop, analyze_scalar_evolution (loop, PHI_RESULT (phi))); | |
1760 | ||
1761 | if (!access_fn) | |
1762 | { | |
00518cb1 | 1763 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
1764 | fprintf (vect_dump, "No Access function."); |
1765 | return false; | |
1766 | } | |
1767 | ||
00518cb1 | 1768 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
1769 | { |
1770 | fprintf (vect_dump, "Access function of PHI: "); | |
1771 | print_generic_expr (vect_dump, access_fn, TDF_SLIM); | |
1772 | } | |
1773 | ||
1774 | evolution_part = evolution_part_in_loop_num (access_fn, loop->num); | |
1775 | ||
1776 | if (evolution_part == NULL_TREE) | |
88088c03 | 1777 | { |
00518cb1 | 1778 | if (vect_print_dump_info (REPORT_DETAILS)) |
88088c03 DN |
1779 | fprintf (vect_dump, "No evolution."); |
1780 | return false; | |
1781 | } | |
f7064d11 DN |
1782 | |
1783 | /* FORNOW: We do not transform initial conditions of IVs | |
1784 | which evolution functions are a polynomial of degree >= 2. */ | |
1785 | ||
1786 | if (tree_is_chrec (evolution_part)) | |
1787 | return false; | |
1788 | } | |
1789 | ||
1790 | return true; | |
1791 | } | |
1792 | ||
1793 | ||
1794 | /* Function vect_get_loop_niters. | |
1795 | ||
1796 | Determine how many iterations the loop is executed. | |
1797 | If an expression that represents the number of iterations | |
1798 | can be constructed, place it in NUMBER_OF_ITERATIONS. | |
1799 | Return the loop exit condition. */ | |
1800 | ||
1801 | static tree | |
1802 | vect_get_loop_niters (struct loop *loop, tree *number_of_iterations) | |
1803 | { | |
1804 | tree niters; | |
1805 | ||
00518cb1 | 1806 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
1807 | fprintf (vect_dump, "=== get_loop_niters ==="); |
1808 | ||
1809 | niters = number_of_iterations_in_loop (loop); | |
1810 | ||
1811 | if (niters != NULL_TREE | |
1812 | && niters != chrec_dont_know) | |
1813 | { | |
1814 | *number_of_iterations = niters; | |
1815 | ||
00518cb1 | 1816 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
1817 | { |
1818 | fprintf (vect_dump, "==> get_loop_niters:" ); | |
1819 | print_generic_expr (vect_dump, *number_of_iterations, TDF_SLIM); | |
1820 | } | |
1821 | } | |
1822 | ||
1823 | return get_loop_exit_condition (loop); | |
1824 | } | |
1825 | ||
1826 | ||
1827 | /* Function vect_analyze_loop_form. | |
1828 | ||
1829 | Verify the following restrictions (some may be relaxed in the future): | |
1830 | - it's an inner-most loop | |
1831 | - number of BBs = 2 (which are the loop header and the latch) | |
1832 | - the loop has a pre-header | |
1833 | - the loop has a single entry and exit | |
1834 | - the loop exit condition is simple enough, and the number of iterations | |
1835 | can be analyzed (a countable loop). */ | |
1836 | ||
1837 | static loop_vec_info | |
1838 | vect_analyze_loop_form (struct loop *loop) | |
1839 | { | |
1840 | loop_vec_info loop_vinfo; | |
1841 | tree loop_cond; | |
1842 | tree number_of_iterations = NULL; | |
f7064d11 | 1843 | |
00518cb1 | 1844 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
1845 | fprintf (vect_dump, "=== vect_analyze_loop_form ==="); |
1846 | ||
1847 | if (loop->inner) | |
1848 | { | |
00518cb1 | 1849 | if (vect_print_dump_info (REPORT_OUTER_LOOPS)) |
f7064d11 DN |
1850 | fprintf (vect_dump, "not vectorized: nested loop."); |
1851 | return NULL; | |
1852 | } | |
1853 | ||
1854 | if (!loop->single_exit | |
1855 | || loop->num_nodes != 2 | |
70388d94 | 1856 | || EDGE_COUNT (loop->header->preds) != 2) |
f7064d11 | 1857 | { |
00518cb1 | 1858 | if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS)) |
f7064d11 DN |
1859 | { |
1860 | if (!loop->single_exit) | |
1861 | fprintf (vect_dump, "not vectorized: multiple exits."); | |
1862 | else if (loop->num_nodes != 2) | |
1863 | fprintf (vect_dump, "not vectorized: too many BBs in loop."); | |
1864 | else if (EDGE_COUNT (loop->header->preds) != 2) | |
1865 | fprintf (vect_dump, "not vectorized: too many incoming edges."); | |
f7064d11 DN |
1866 | } |
1867 | ||
1868 | return NULL; | |
1869 | } | |
1870 | ||
1871 | /* We assume that the loop exit condition is at the end of the loop. i.e, | |
1872 | that the loop is represented as a do-while (with a proper if-guard | |
1873 | before the loop if needed), where the loop header contains all the | |
1874 | executable statements, and the latch is empty. */ | |
1875 | if (!empty_block_p (loop->latch)) | |
1876 | { | |
00518cb1 | 1877 | if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS)) |
cc9795d4 | 1878 | fprintf (vect_dump, "not vectorized: unexpected loop form."); |
f7064d11 DN |
1879 | return NULL; |
1880 | } | |
1881 | ||
f7064d11 | 1882 | /* Make sure there exists a single-predecessor exit bb: */ |
c5cbcccf | 1883 | if (!single_pred_p (loop->single_exit->dest)) |
f7064d11 | 1884 | { |
ac59a959 DN |
1885 | edge e = loop->single_exit; |
1886 | if (!(e->flags & EDGE_ABNORMAL)) | |
1887 | { | |
d401de95 | 1888 | split_loop_exit_edge (e); |
00518cb1 | 1889 | if (vect_print_dump_info (REPORT_DETAILS)) |
ac59a959 | 1890 | fprintf (vect_dump, "split exit edge."); |
ac59a959 DN |
1891 | } |
1892 | else | |
1893 | { | |
00518cb1 | 1894 | if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS)) |
ac59a959 DN |
1895 | fprintf (vect_dump, "not vectorized: abnormal loop exit edge."); |
1896 | return NULL; | |
1897 | } | |
f7064d11 | 1898 | } |
f7064d11 DN |
1899 | |
1900 | if (empty_block_p (loop->header)) | |
1901 | { | |
00518cb1 | 1902 | if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS)) |
f7064d11 DN |
1903 | fprintf (vect_dump, "not vectorized: empty loop."); |
1904 | return NULL; | |
1905 | } | |
1906 | ||
1907 | loop_cond = vect_get_loop_niters (loop, &number_of_iterations); | |
1908 | if (!loop_cond) | |
1909 | { | |
00518cb1 | 1910 | if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS)) |
f7064d11 DN |
1911 | fprintf (vect_dump, "not vectorized: complicated exit condition."); |
1912 | return NULL; | |
1913 | } | |
1914 | ||
1915 | if (!number_of_iterations) | |
1916 | { | |
00518cb1 | 1917 | if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS)) |
f7064d11 DN |
1918 | fprintf (vect_dump, |
1919 | "not vectorized: number of iterations cannot be computed."); | |
1920 | return NULL; | |
1921 | } | |
1922 | ||
1923 | if (chrec_contains_undetermined (number_of_iterations)) | |
1924 | { | |
00518cb1 | 1925 | if (vect_print_dump_info (REPORT_BAD_FORM_LOOPS)) |
f7064d11 DN |
1926 | fprintf (vect_dump, "Infinite number of iterations."); |
1927 | return false; | |
1928 | } | |
1929 | ||
1930 | loop_vinfo = new_loop_vec_info (loop); | |
1931 | LOOP_VINFO_NITERS (loop_vinfo) = number_of_iterations; | |
1932 | ||
1933 | if (!LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo)) | |
1934 | { | |
00518cb1 | 1935 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
1936 | { |
1937 | fprintf (vect_dump, "Symbolic number of iterations is "); | |
1938 | print_generic_expr (vect_dump, number_of_iterations, TDF_DETAILS); | |
1939 | } | |
1940 | } | |
1941 | else | |
1942 | if (LOOP_VINFO_INT_NITERS (loop_vinfo) == 0) | |
1943 | { | |
00518cb1 | 1944 | if (vect_print_dump_info (REPORT_UNVECTORIZED_LOOPS)) |
f7064d11 DN |
1945 | fprintf (vect_dump, "not vectorized: number of iterations = 0."); |
1946 | return NULL; | |
1947 | } | |
1948 | ||
1949 | LOOP_VINFO_EXIT_COND (loop_vinfo) = loop_cond; | |
f7064d11 DN |
1950 | |
1951 | return loop_vinfo; | |
1952 | } | |
1953 | ||
1954 | ||
1955 | /* Function vect_analyze_loop. | |
1956 | ||
1957 | Apply a set of analyses on LOOP, and create a loop_vec_info struct | |
1958 | for it. The different analyses will record information in the | |
1959 | loop_vec_info struct. */ | |
1960 | loop_vec_info | |
1961 | vect_analyze_loop (struct loop *loop) | |
1962 | { | |
1963 | bool ok; | |
1964 | loop_vec_info loop_vinfo; | |
1965 | ||
00518cb1 | 1966 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
1967 | fprintf (vect_dump, "===== analyze_loop_nest ====="); |
1968 | ||
1969 | /* Check the CFG characteristics of the loop (nesting, entry/exit, etc. */ | |
1970 | ||
1971 | loop_vinfo = vect_analyze_loop_form (loop); | |
1972 | if (!loop_vinfo) | |
1973 | { | |
00518cb1 | 1974 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
1975 | fprintf (vect_dump, "bad loop form."); |
1976 | return NULL; | |
1977 | } | |
1978 | ||
1979 | /* Find all data references in the loop (which correspond to vdefs/vuses) | |
1980 | and analyze their evolution in the loop. | |
1981 | ||
1982 | FORNOW: Handle only simple, array references, which | |
1983 | alignment can be forced, and aligned pointer-references. */ | |
1984 | ||
1985 | ok = vect_analyze_data_refs (loop_vinfo); | |
1986 | if (!ok) | |
1987 | { | |
00518cb1 | 1988 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
1989 | fprintf (vect_dump, "bad data references."); |
1990 | destroy_loop_vec_info (loop_vinfo); | |
1991 | return NULL; | |
1992 | } | |
1993 | ||
88088c03 DN |
1994 | /* Classify all cross-iteration scalar data-flow cycles. |
1995 | Cross-iteration cycles caused by virtual phis are analyzed separately. */ | |
1996 | ||
1997 | vect_analyze_scalar_cycles (loop_vinfo); | |
1998 | ||
f7064d11 DN |
1999 | /* Data-flow analysis to detect stmts that do not need to be vectorized. */ |
2000 | ||
2001 | ok = vect_mark_stmts_to_be_vectorized (loop_vinfo); | |
2002 | if (!ok) | |
2003 | { | |
00518cb1 | 2004 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
2005 | fprintf (vect_dump, "unexpected pattern."); |
2006 | destroy_loop_vec_info (loop_vinfo); | |
2007 | return NULL; | |
2008 | } | |
2009 | ||
c12cc930 KB |
2010 | /* Analyze the alignment of the data-refs in the loop. |
2011 | Fail if a data reference is found that cannot be vectorized. */ | |
2012 | ||
2013 | ok = vect_analyze_data_refs_alignment (loop_vinfo); | |
2014 | if (!ok) | |
2015 | { | |
2016 | if (vect_print_dump_info (REPORT_DETAILS)) | |
2017 | fprintf (vect_dump, "bad data alignment."); | |
2018 | destroy_loop_vec_info (loop_vinfo); | |
2019 | return NULL; | |
2020 | } | |
2021 | ||
b52485c6 DP |
2022 | ok = vect_determine_vectorization_factor (loop_vinfo); |
2023 | if (!ok) | |
2024 | { | |
00518cb1 | 2025 | if (vect_print_dump_info (REPORT_DETAILS)) |
b52485c6 DP |
2026 | fprintf (vect_dump, "can't determine vectorization factor."); |
2027 | destroy_loop_vec_info (loop_vinfo); | |
2028 | return NULL; | |
2029 | } | |
2030 | ||
f7064d11 DN |
2031 | /* Analyze data dependences between the data-refs in the loop. |
2032 | FORNOW: fail at the first data dependence that we encounter. */ | |
2033 | ||
2034 | ok = vect_analyze_data_ref_dependences (loop_vinfo); | |
2035 | if (!ok) | |
2036 | { | |
00518cb1 | 2037 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
2038 | fprintf (vect_dump, "bad data dependence."); |
2039 | destroy_loop_vec_info (loop_vinfo); | |
2040 | return NULL; | |
2041 | } | |
2042 | ||
2043 | /* Analyze the access patterns of the data-refs in the loop (consecutive, | |
2044 | complex, etc.). FORNOW: Only handle consecutive access pattern. */ | |
2045 | ||
2046 | ok = vect_analyze_data_ref_accesses (loop_vinfo); | |
2047 | if (!ok) | |
2048 | { | |
00518cb1 | 2049 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
2050 | fprintf (vect_dump, "bad data access."); |
2051 | destroy_loop_vec_info (loop_vinfo); | |
2052 | return NULL; | |
2053 | } | |
2054 | ||
c12cc930 KB |
2055 | /* This pass will decide on using loop versioning and/or loop peeling in |
2056 | order to enhance the alignment of data references in the loop. */ | |
f7064d11 | 2057 | |
c12cc930 | 2058 | ok = vect_enhance_data_refs_alignment (loop_vinfo); |
f7064d11 DN |
2059 | if (!ok) |
2060 | { | |
00518cb1 | 2061 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
2062 | fprintf (vect_dump, "bad data alignment."); |
2063 | destroy_loop_vec_info (loop_vinfo); | |
2064 | return NULL; | |
2065 | } | |
2066 | ||
2067 | /* Scan all the operations in the loop and make sure they are | |
2068 | vectorizable. */ | |
2069 | ||
2070 | ok = vect_analyze_operations (loop_vinfo); | |
2071 | if (!ok) | |
2072 | { | |
00518cb1 | 2073 | if (vect_print_dump_info (REPORT_DETAILS)) |
f7064d11 DN |
2074 | fprintf (vect_dump, "bad operation or unsupported loop bound."); |
2075 | destroy_loop_vec_info (loop_vinfo); | |
2076 | return NULL; | |
2077 | } | |
2078 | ||
2079 | LOOP_VINFO_VECTORIZABLE_P (loop_vinfo) = 1; | |
2080 | ||
2081 | return loop_vinfo; | |
2082 | } |