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c6bb733d | 1 | /* Single entry single exit control flow regions. |
8e8f6434 | 2 | Copyright (C) 2008-2018 Free Software Foundation, Inc. |
c6bb733d | 3 | Contributed by Jan Sjodin <jan.sjodin@amd.com> and |
4 | Sebastian Pop <sebastian.pop@amd.com>. | |
5 | ||
6 | This file is part of GCC. | |
7 | ||
8 | GCC is free software; you can redistribute it and/or modify | |
9 | it under the terms of the GNU General Public License as published by | |
10 | the Free Software Foundation; either version 3, or (at your option) | |
11 | any later version. | |
12 | ||
13 | GCC is distributed in the hope that it will be useful, | |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | GNU General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
19 | along with GCC; see the file COPYING3. If not see | |
20 | <http://www.gnu.org/licenses/>. */ | |
21 | ||
22 | #include "config.h" | |
23 | #include "system.h" | |
24 | #include "coretypes.h" | |
9ef16211 | 25 | #include "backend.h" |
0d9585ca | 26 | #include "tree.h" |
9ef16211 | 27 | #include "gimple.h" |
7c29e30e | 28 | #include "cfghooks.h" |
29 | #include "tree-pass.h" | |
9ef16211 | 30 | #include "ssa.h" |
ce084dfc | 31 | #include "tree-pretty-print.h" |
7c29e30e | 32 | #include "fold-const.h" |
a8783bee | 33 | #include "gimplify.h" |
dcf1a1ec | 34 | #include "gimple-iterator.h" |
30162daa | 35 | #include "gimple-pretty-print.h" |
e795d6e1 | 36 | #include "gimplify-me.h" |
073c1fd5 | 37 | #include "tree-cfg.h" |
073c1fd5 | 38 | #include "tree-ssa-loop.h" |
39 | #include "tree-into-ssa.h" | |
c6bb733d | 40 | #include "cfgloop.h" |
c6bb733d | 41 | #include "tree-data-ref.h" |
42 | #include "tree-scalar-evolution.h" | |
0f4161b1 | 43 | #include "tree-ssa-propagate.h" |
4c03ed5f | 44 | #include "cfganal.h" |
45 | #include "sese.h" | |
c6bb733d | 46 | |
c6bb733d | 47 | /* For a USE in BB, if BB is outside REGION, mark the USE in the |
48 | LIVEOUTS set. */ | |
49 | ||
50 | static void | |
f032380c | 51 | sese_build_liveouts_use (sese_info_p region, bitmap liveouts, basic_block bb, |
c6bb733d | 52 | tree use) |
53 | { | |
f032380c | 54 | gcc_assert (!bb_in_sese_p (bb, region->region)); |
c6bb733d | 55 | if (TREE_CODE (use) != SSA_NAME) |
56 | return; | |
57 | ||
f1537fda | 58 | basic_block def_bb = gimple_bb (SSA_NAME_DEF_STMT (use)); |
c6bb733d | 59 | |
f032380c | 60 | if (!def_bb || !bb_in_sese_p (def_bb, region->region)) |
c6bb733d | 61 | return; |
62 | ||
f1537fda | 63 | unsigned ver = SSA_NAME_VERSION (use); |
c6bb733d | 64 | bitmap_set_bit (liveouts, ver); |
65 | } | |
66 | ||
67 | /* Marks for rewrite all the SSA_NAMES defined in REGION and that are | |
68 | used in BB that is outside of the REGION. */ | |
69 | ||
70 | static void | |
74936b22 | 71 | sese_build_liveouts_bb (sese_info_p region, basic_block bb) |
c6bb733d | 72 | { |
c6bb733d | 73 | ssa_op_iter iter; |
74 | use_operand_p use_p; | |
75 | ||
74936b22 | 76 | for (gphi_iterator bsi = gsi_start_phis (bb); !gsi_end_p (bsi); |
77 | gsi_next (&bsi)) | |
78 | FOR_EACH_PHI_ARG (use_p, bsi.phi (), iter, SSA_OP_USE) | |
79 | sese_build_liveouts_use (region, region->liveout, | |
80 | bb, USE_FROM_PTR (use_p)); | |
c6bb733d | 81 | |
1a91d914 | 82 | for (gimple_stmt_iterator bsi = gsi_start_bb (bb); !gsi_end_p (bsi); |
83 | gsi_next (&bsi)) | |
3f6c0a40 | 84 | { |
42acab1c | 85 | gimple *stmt = gsi_stmt (bsi); |
3f6c0a40 | 86 | |
74936b22 | 87 | bitmap liveouts = region->liveout; |
3f6c0a40 | 88 | if (is_gimple_debug (stmt)) |
74936b22 | 89 | liveouts = region->debug_liveout; |
3f6c0a40 | 90 | |
74936b22 | 91 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) |
3f6c0a40 | 92 | sese_build_liveouts_use (region, liveouts, bb, USE_FROM_PTR (use_p)); |
93 | } | |
94 | } | |
95 | ||
3f6c0a40 | 96 | /* Reset debug stmts that reference SSA_NAMES defined in REGION that |
97 | are not marked as liveouts. */ | |
98 | ||
99 | static void | |
74936b22 | 100 | sese_reset_debug_liveouts (sese_info_p region) |
3f6c0a40 | 101 | { |
74936b22 | 102 | bitmap_iterator bi; |
103 | unsigned i; | |
104 | EXECUTE_IF_AND_COMPL_IN_BITMAP (region->debug_liveout, region->liveout, | |
105 | 0, i, bi) | |
3f6c0a40 | 106 | { |
74936b22 | 107 | tree name = ssa_name (i); |
108 | auto_vec<gimple *, 4> stmts; | |
109 | gimple *use_stmt; | |
110 | imm_use_iterator use_iter; | |
111 | FOR_EACH_IMM_USE_STMT (use_stmt, use_iter, name) | |
112 | { | |
113 | if (! is_gimple_debug (use_stmt) | |
114 | || bb_in_sese_p (gimple_bb (use_stmt), region->region)) | |
115 | continue; | |
116 | stmts.safe_push (use_stmt); | |
117 | } | |
118 | while (!stmts.is_empty ()) | |
119 | { | |
120 | gimple *stmt = stmts.pop (); | |
121 | gimple_debug_bind_reset_value (stmt); | |
122 | update_stmt (stmt); | |
123 | } | |
3f6c0a40 | 124 | } |
c6bb733d | 125 | } |
126 | ||
127 | /* Build the LIVEOUTS of REGION: the set of variables defined inside | |
128 | and used outside the REGION. */ | |
129 | ||
74936b22 | 130 | void |
131 | sese_build_liveouts (sese_info_p region) | |
c6bb733d | 132 | { |
133 | basic_block bb; | |
134 | ||
74936b22 | 135 | gcc_assert (region->liveout == NULL |
136 | && region->debug_liveout == NULL); | |
137 | ||
138 | region->liveout = BITMAP_ALLOC (NULL); | |
139 | region->debug_liveout = BITMAP_ALLOC (NULL); | |
140 | ||
f1537fda | 141 | /* FIXME: We could start iterating form the successor of sese. */ |
fc00614f | 142 | FOR_EACH_BB_FN (bb, cfun) |
f032380c | 143 | if (!bb_in_sese_p (bb, region->region)) |
74936b22 | 144 | sese_build_liveouts_bb (region, bb); |
c6bb733d | 145 | } |
146 | ||
147 | /* Builds a new SESE region from edges ENTRY and EXIT. */ | |
148 | ||
f032380c | 149 | sese_info_p |
150 | new_sese_info (edge entry, edge exit) | |
c6bb733d | 151 | { |
f032380c | 152 | sese_info_p region = XNEW (struct sese_info_t); |
c6bb733d | 153 | |
f032380c | 154 | region->region.entry = entry; |
155 | region->region.exit = exit; | |
74936b22 | 156 | region->liveout = NULL; |
157 | region->debug_liveout = NULL; | |
30162daa | 158 | region->params.create (3); |
cbd0be31 | 159 | region->rename_map = new hash_map <tree, tree>; |
0e526381 | 160 | region->bbs.create (3); |
c3a14714 | 161 | |
c6bb733d | 162 | return region; |
163 | } | |
164 | ||
165 | /* Deletes REGION. */ | |
166 | ||
167 | void | |
f032380c | 168 | free_sese_info (sese_info_p region) |
c6bb733d | 169 | { |
30162daa | 170 | region->params.release (); |
74936b22 | 171 | BITMAP_FREE (region->liveout); |
172 | BITMAP_FREE (region->debug_liveout); | |
30162daa | 173 | |
30162daa | 174 | delete region->rename_map; |
30162daa | 175 | region->rename_map = NULL; |
30162daa | 176 | region->bbs.release (); |
c6bb733d | 177 | |
c6bb733d | 178 | XDELETE (region); |
179 | } | |
180 | ||
181 | /* Add exit phis for USE on EXIT. */ | |
182 | ||
183 | static void | |
184 | sese_add_exit_phis_edge (basic_block exit, tree use, edge false_e, edge true_e) | |
185 | { | |
1a91d914 | 186 | gphi *phi = create_phi_node (NULL_TREE, exit); |
9c06f260 | 187 | create_new_def_for (use, phi, gimple_phi_result_ptr (phi)); |
60d535d2 | 188 | add_phi_arg (phi, use, false_e, UNKNOWN_LOCATION); |
189 | add_phi_arg (phi, use, true_e, UNKNOWN_LOCATION); | |
fa4dba85 | 190 | update_stmt (phi); |
c6bb733d | 191 | } |
192 | ||
193 | /* Insert in the block BB phi nodes for variables defined in REGION | |
194 | and used outside the REGION. The code generation moves REGION in | |
195 | the else clause of an "if (1)" and generates code in the then | |
196 | clause that is at this point empty: | |
197 | ||
198 | | if (1) | |
199 | | empty; | |
200 | | else | |
201 | | REGION; | |
202 | */ | |
203 | ||
204 | void | |
f032380c | 205 | sese_insert_phis_for_liveouts (sese_info_p region, basic_block bb, |
c6bb733d | 206 | edge false_e, edge true_e) |
207 | { | |
c64f38bf | 208 | if (MAY_HAVE_DEBUG_BIND_STMTS) |
74936b22 | 209 | sese_reset_debug_liveouts (region); |
210 | ||
c6bb733d | 211 | unsigned i; |
212 | bitmap_iterator bi; | |
74936b22 | 213 | EXECUTE_IF_SET_IN_BITMAP (region->liveout, 0, i, bi) |
30162daa | 214 | if (!virtual_operand_p (ssa_name (i))) |
215 | sese_add_exit_phis_edge (bb, ssa_name (i), false_e, true_e); | |
c6bb733d | 216 | } |
217 | ||
30162daa | 218 | /* Returns the outermost loop in SCOP that contains BB. */ |
c6bb733d | 219 | |
220 | struct loop * | |
f032380c | 221 | outermost_loop_in_sese_1 (sese_l ®ion, basic_block bb) |
c6bb733d | 222 | { |
223 | struct loop *nest; | |
224 | ||
225 | nest = bb->loop_father; | |
226 | while (loop_outer (nest) | |
227 | && loop_in_sese_p (loop_outer (nest), region)) | |
228 | nest = loop_outer (nest); | |
229 | ||
230 | return nest; | |
231 | } | |
232 | ||
443b5bd0 | 233 | /* Same as outermost_loop_in_sese_1, returns the outermost loop |
234 | containing BB in REGION, but makes sure that the returned loop | |
235 | belongs to the REGION, and so this returns the first loop in the | |
236 | REGION when the loop containing BB does not belong to REGION. */ | |
237 | ||
238 | loop_p | |
f032380c | 239 | outermost_loop_in_sese (sese_l ®ion, basic_block bb) |
443b5bd0 | 240 | { |
241 | loop_p nest = outermost_loop_in_sese_1 (region, bb); | |
242 | ||
243 | if (loop_in_sese_p (nest, region)) | |
244 | return nest; | |
245 | ||
246 | /* When the basic block BB does not belong to a loop in the region, | |
247 | return the first loop in the region. */ | |
248 | nest = nest->inner; | |
249 | while (nest) | |
250 | if (loop_in_sese_p (nest, region)) | |
251 | break; | |
252 | else | |
253 | nest = nest->next; | |
254 | ||
255 | gcc_assert (nest); | |
256 | return nest; | |
257 | } | |
258 | ||
2bca9286 | 259 | /* Returns the first successor edge of BB with EDGE_TRUE_VALUE flag set. */ |
260 | ||
261 | edge | |
262 | get_true_edge_from_guard_bb (basic_block bb) | |
263 | { | |
264 | edge e; | |
265 | edge_iterator ei; | |
266 | ||
267 | FOR_EACH_EDGE (e, ei, bb->succs) | |
268 | if (e->flags & EDGE_TRUE_VALUE) | |
269 | return e; | |
270 | ||
271 | gcc_unreachable (); | |
272 | return NULL; | |
273 | } | |
274 | ||
275 | /* Returns the first successor edge of BB with EDGE_TRUE_VALUE flag cleared. */ | |
276 | ||
277 | edge | |
278 | get_false_edge_from_guard_bb (basic_block bb) | |
279 | { | |
280 | edge e; | |
281 | edge_iterator ei; | |
282 | ||
283 | FOR_EACH_EDGE (e, ei, bb->succs) | |
284 | if (!(e->flags & EDGE_TRUE_VALUE)) | |
285 | return e; | |
286 | ||
287 | gcc_unreachable (); | |
288 | return NULL; | |
289 | } | |
290 | ||
c6bb733d | 291 | /* Moves REGION in a condition expression: |
292 | | if (1) | |
293 | | ; | |
294 | | else | |
295 | | REGION; | |
296 | */ | |
297 | ||
298 | ifsese | |
f032380c | 299 | move_sese_in_condition (sese_info_p region) |
c6bb733d | 300 | { |
4c03ed5f | 301 | basic_block region_entry_dest = region->region.entry->dest; |
f032380c | 302 | basic_block pred_block = split_edge (region->region.entry); |
4c03ed5f | 303 | basic_block merge_block = split_edge (region->region.exit); |
304 | ||
305 | edge true_edge = make_edge (pred_block, merge_block, EDGE_TRUE_VALUE); | |
306 | edge false_edge = find_edge (pred_block, region_entry_dest); | |
307 | false_edge->flags &= ~EDGE_FALLTHRU; | |
308 | false_edge->flags |= EDGE_FALSE_VALUE; | |
309 | gimple_stmt_iterator gsi = gsi_last_bb (pred_block); | |
310 | gcond *cond = gimple_build_cond (NE_EXPR, integer_one_node, integer_zero_node, | |
311 | NULL_TREE, NULL_TREE); | |
312 | gsi_insert_after (&gsi, cond, GSI_CONTINUE_LINKING); | |
313 | if (dom_info_available_p (CDI_DOMINATORS)) | |
314 | set_immediate_dominator (CDI_DOMINATORS, merge_block, pred_block); | |
315 | ||
316 | ifsese if_region = XNEW (ifsese_s); | |
317 | if_region->region = XCNEW (sese_info_t); | |
318 | if_region->true_region = XCNEW (sese_info_t); | |
319 | if_region->false_region = XCNEW (sese_info_t); | |
320 | if_region->region->region.entry = single_pred_edge (pred_block); | |
321 | if_region->region->region.exit = single_succ_edge (merge_block); | |
322 | if_region->false_region->region.entry = false_edge; | |
323 | if_region->false_region->region.exit = region->region.exit; | |
324 | if_region->true_region->region.entry = true_edge; | |
325 | if_region->true_region->region.exit | |
326 | = single_succ_edge (split_edge (true_edge)); | |
c6bb733d | 327 | |
74936b22 | 328 | region->region = if_region->false_region->region; |
329 | ||
c6bb733d | 330 | return if_region; |
331 | } | |
332 | ||
2487de19 | 333 | /* Replaces the condition of the IF_REGION with CONDITION: |
334 | | if (CONDITION) | |
335 | | true_region; | |
336 | | else | |
337 | | false_region; | |
338 | */ | |
339 | ||
340 | void | |
341 | set_ifsese_condition (ifsese if_region, tree condition) | |
342 | { | |
f032380c | 343 | sese_info_p region = if_region->region; |
344 | edge entry = region->region.entry; | |
2487de19 | 345 | basic_block bb = entry->dest; |
42acab1c | 346 | gimple *last = last_stmt (bb); |
2487de19 | 347 | gimple_stmt_iterator gsi = gsi_last_bb (bb); |
1a91d914 | 348 | gcond *cond_stmt; |
2487de19 | 349 | |
350 | gcc_assert (gimple_code (last) == GIMPLE_COND); | |
351 | ||
352 | gsi_remove (&gsi, true); | |
353 | gsi = gsi_last_bb (bb); | |
354 | condition = force_gimple_operand_gsi (&gsi, condition, true, NULL, | |
355 | false, GSI_NEW_STMT); | |
356 | cond_stmt = gimple_build_cond_from_tree (condition, NULL_TREE, NULL_TREE); | |
357 | gsi = gsi_last_bb (bb); | |
358 | gsi_insert_after (&gsi, cond_stmt, GSI_NEW_STMT); | |
359 | } | |
360 | ||
9c0cc377 | 361 | /* Return true when T is defined outside REGION or when no definitions are |
13f421d5 | 362 | variant in REGION. When HAS_VDEFS is a valid pointer, sets HAS_VDEFS to true |
363 | when T depends on memory that may change in REGION. */ | |
fa4dba85 | 364 | |
9c0cc377 | 365 | bool |
d523d0c4 | 366 | invariant_in_sese_p_rec (tree t, const sese_l ®ion, bool *has_vdefs) |
fa4dba85 | 367 | { |
fa4dba85 | 368 | if (!defined_in_sese_p (t, region)) |
369 | return true; | |
370 | ||
42acab1c | 371 | gimple *stmt = SSA_NAME_DEF_STMT (t); |
fa4dba85 | 372 | |
373 | if (gimple_code (stmt) == GIMPLE_PHI | |
374 | || gimple_code (stmt) == GIMPLE_CALL) | |
375 | return false; | |
376 | ||
9c0cc377 | 377 | /* VDEF is variant when it is in the region. */ |
ec6135ce | 378 | if (gimple_vdef (stmt)) |
13f421d5 | 379 | { |
380 | if (has_vdefs) | |
381 | *has_vdefs = true; | |
382 | return false; | |
383 | } | |
9c0cc377 | 384 | |
385 | /* A VUSE may or may not be variant following the VDEFs. */ | |
386 | if (tree vuse = gimple_vuse (stmt)) | |
13f421d5 | 387 | return invariant_in_sese_p_rec (vuse, region, has_vdefs); |
9c0cc377 | 388 | |
30162daa | 389 | ssa_op_iter iter; |
390 | use_operand_p use_p; | |
fa4dba85 | 391 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) |
392 | { | |
393 | tree use = USE_FROM_PTR (use_p); | |
9c0cc377 | 394 | |
fa4dba85 | 395 | if (!defined_in_sese_p (use, region)) |
396 | continue; | |
397 | ||
13f421d5 | 398 | if (!invariant_in_sese_p_rec (use, region, has_vdefs)) |
fa4dba85 | 399 | return false; |
400 | } | |
401 | ||
402 | return true; | |
403 | } | |
404 | ||
c604a230 | 405 | /* Return true when DEF can be analyzed in REGION by the scalar |
406 | evolution analyzer. */ | |
407 | ||
408 | bool | |
409 | scev_analyzable_p (tree def, sese_l ®ion) | |
410 | { | |
411 | loop_p loop; | |
412 | tree scev; | |
413 | tree type = TREE_TYPE (def); | |
414 | ||
415 | /* When Graphite generates code for a scev, the code generator | |
416 | expresses the scev in function of a single induction variable. | |
417 | This is unsafe for floating point computations, as it may replace | |
418 | a floating point sum reduction with a multiplication. The | |
419 | following test returns false for non integer types to avoid such | |
420 | problems. */ | |
421 | if (!INTEGRAL_TYPE_P (type) | |
422 | && !POINTER_TYPE_P (type)) | |
423 | return false; | |
424 | ||
425 | loop = loop_containing_stmt (SSA_NAME_DEF_STMT (def)); | |
426 | scev = scalar_evolution_in_region (region, loop, def); | |
427 | ||
51a2c146 | 428 | return (!chrec_contains_undetermined (scev) |
429 | && (TREE_CODE (scev) != SSA_NAME | |
430 | || !defined_in_sese_p (scev, region)) | |
431 | && scev_is_linear_expression (scev) | |
432 | && (! loop | |
433 | || ! loop_in_sese_p (loop, region) | |
434 | || ! chrec_contains_symbols_defined_in_loop (scev, loop->num))); | |
c604a230 | 435 | } |
436 | ||
c6bb733d | 437 | /* Returns the scalar evolution of T in REGION. Every variable that |
438 | is not defined in the REGION is considered a parameter. */ | |
439 | ||
440 | tree | |
d523d0c4 | 441 | scalar_evolution_in_region (const sese_l ®ion, loop_p loop, tree t) |
c6bb733d | 442 | { |
ae6346fd | 443 | /* SCOP parameters. */ |
444 | if (TREE_CODE (t) == SSA_NAME | |
445 | && !defined_in_sese_p (t, region)) | |
446 | return t; | |
447 | ||
44e2f332 | 448 | if (!loop_in_sese_p (loop, region)) |
449 | loop = NULL; | |
13f421d5 | 450 | |
44e2f332 | 451 | return instantiate_scev (region.entry, loop, |
452 | analyze_scalar_evolution (loop, t)); | |
c6bb733d | 453 | } |
c1616982 | 454 | |
74936b22 | 455 | /* Return true if BB is empty, contains only DEBUG_INSNs. */ |
456 | ||
457 | bool | |
458 | sese_trivially_empty_bb_p (basic_block bb) | |
459 | { | |
460 | gimple_stmt_iterator gsi; | |
461 | ||
462 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
bce107d7 | 463 | if (!is_gimple_debug (gsi_stmt (gsi)) |
74936b22 | 464 | && gimple_code (gsi_stmt (gsi)) != GIMPLE_LABEL) |
465 | return false; | |
466 | ||
467 | return true; | |
468 | } | |
469 | ||
c1616982 | 470 | /* Pretty print edge E to FILE. */ |
471 | ||
472 | void | |
473 | print_edge (FILE *file, const_edge e) | |
474 | { | |
475 | fprintf (file, "edge (bb_%d, bb_%d)", e->src->index, e->dest->index); | |
476 | } | |
477 | ||
478 | /* Pretty print sese S to FILE. */ | |
479 | ||
480 | void | |
481 | print_sese (FILE *file, const sese_l &s) | |
482 | { | |
483 | fprintf (file, "(entry_"); print_edge (file, s.entry); | |
484 | fprintf (file, ", exit_"); print_edge (file, s.exit); | |
485 | fprintf (file, ")\n"); | |
486 | } | |
487 | ||
488 | /* Pretty print edge E to STDERR. */ | |
489 | ||
490 | DEBUG_FUNCTION void | |
491 | debug_edge (const_edge e) | |
492 | { | |
493 | print_edge (stderr, e); | |
494 | } | |
495 | ||
496 | /* Pretty print sese S to STDERR. */ | |
497 | ||
498 | DEBUG_FUNCTION void | |
499 | debug_sese (const sese_l &s) | |
500 | { | |
501 | print_sese (stderr, s); | |
502 | } |