Line data Source code
1 : /* High-level loop manipulation functions.
2 : Copyright (C) 2004-2026 Free Software Foundation, Inc.
3 :
4 : This file is part of GCC.
5 :
6 : GCC is free software; you can redistribute it and/or modify it
7 : under the terms of the GNU General Public License as published by the
8 : Free Software Foundation; either version 3, or (at your option) any
9 : later version.
10 :
11 : GCC is distributed in the hope that it will be useful, but WITHOUT
12 : ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 : FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 : for more details.
15 :
16 : You should have received a copy of the GNU General Public License
17 : along with GCC; see the file COPYING3. If not see
18 : <http://www.gnu.org/licenses/>. */
19 :
20 : #include "config.h"
21 : #include "system.h"
22 : #include "coretypes.h"
23 : #include "backend.h"
24 : #include "tree.h"
25 : #include "gimple.h"
26 : #include "cfghooks.h"
27 : #include "tree-pass.h" /* ??? for TODO_update_ssa but this isn't a pass. */
28 : #include "ssa.h"
29 : #include "gimple-pretty-print.h"
30 : #include "fold-const.h"
31 : #include "cfganal.h"
32 : #include "gimplify.h"
33 : #include "gimple-iterator.h"
34 : #include "gimplify-me.h"
35 : #include "tree-cfg.h"
36 : #include "tree-ssa-loop-ivopts.h"
37 : #include "tree-ssa-loop-manip.h"
38 : #include "tree-ssa-loop-niter.h"
39 : #include "tree-ssa-loop.h"
40 : #include "tree-into-ssa.h"
41 : #include "tree-ssa.h"
42 : #include "cfgloop.h"
43 : #include "tree-scalar-evolution.h"
44 : #include "tree-inline.h"
45 :
46 : /* All bitmaps for rewriting into loop-closed SSA go on this obstack,
47 : so that we can free them all at once. */
48 : static bitmap_obstack loop_renamer_obstack;
49 :
50 : /* Insert IV increment statements STMTS before or after INCR_POS;
51 : AFTER selects which. INCR_POS and AFTER can be computed using
52 : standard_iv_increment_position. */
53 :
54 : void
55 1004597 : insert_iv_increment (gimple_stmt_iterator *incr_pos, bool after,
56 : gimple_seq stmts)
57 : {
58 : /* Prevent the increment from inheriting a bogus location if it is not put
59 : immediately after a statement whose location is known. */
60 1004597 : if (after)
61 : {
62 10815 : gimple_stmt_iterator gsi = *incr_pos;
63 10815 : if (!gsi_end_p (gsi))
64 9326 : gsi_next_nondebug (&gsi);
65 10815 : if (gsi_end_p (gsi))
66 : {
67 10815 : edge e = single_succ_edge (gsi_bb (*incr_pos));
68 10815 : gimple_seq_set_location (stmts, e->goto_locus);
69 : }
70 10815 : gsi_insert_seq_after (incr_pos, stmts, GSI_NEW_STMT);
71 : }
72 : else
73 : {
74 993782 : gimple_stmt_iterator gsi = *incr_pos;
75 993782 : if (!gsi_end_p (gsi) && is_gimple_debug (gsi_stmt (gsi)))
76 0 : gsi_next_nondebug (&gsi);
77 993782 : if (!gsi_end_p (gsi))
78 993282 : gimple_seq_set_location (stmts, gimple_location (gsi_stmt (gsi)));
79 993782 : gsi_insert_seq_before (incr_pos, stmts, GSI_NEW_STMT);
80 : }
81 1004597 : }
82 :
83 : /* Creates an induction variable with value BASE (+/-) STEP * iteration in LOOP.
84 : If INCR_OP is PLUS_EXPR, the induction variable is BASE + STEP * iteration.
85 : If INCR_OP is MINUS_EXPR, the induction variable is BASE - STEP * iteration.
86 : It is expected that neither BASE nor STEP are shared with other expressions
87 : (unless the sharing rules allow this). Use VAR as a base var_decl for it
88 : (if NULL, a new temporary will be created). The increment will occur at
89 : INCR_POS (after it if AFTER is true, before it otherwise). INCR_POS and
90 : AFTER can be computed using standard_iv_increment_position. The ssa versions
91 : of the variable before and after increment will be stored in VAR_BEFORE and
92 : VAR_AFTER (unless they are NULL). */
93 :
94 : void
95 988769 : create_iv (tree base, tree_code incr_op, tree step, tree var, class loop *loop,
96 : gimple_stmt_iterator *incr_pos, bool after, tree *var_before,
97 : tree *var_after)
98 : {
99 988769 : gphi *phi;
100 988769 : tree initial, step1;
101 988769 : gimple_seq stmts;
102 988769 : tree vb, va;
103 988769 : gcc_assert (incr_op == PLUS_EXPR || incr_op == MINUS_EXPR);
104 988769 : edge pe = loop_preheader_edge (loop);
105 :
106 988769 : if (var != NULL_TREE)
107 : {
108 604135 : vb = make_ssa_name (var);
109 604135 : va = make_ssa_name (var);
110 : }
111 : else
112 : {
113 384634 : vb = make_temp_ssa_name (TREE_TYPE (base), NULL, "ivtmp");
114 384634 : va = make_temp_ssa_name (TREE_TYPE (base), NULL, "ivtmp");
115 : }
116 988769 : if (var_before)
117 674426 : *var_before = vb;
118 988769 : if (var_after)
119 981279 : *var_after = va;
120 :
121 : /* For easier readability of the created code, produce MINUS_EXPRs
122 : when suitable. */
123 988769 : if (TREE_CODE (step) == INTEGER_CST)
124 : {
125 932326 : if (TYPE_UNSIGNED (TREE_TYPE (step)))
126 : {
127 930378 : step1 = fold_build1 (NEGATE_EXPR, TREE_TYPE (step), step);
128 930378 : if (tree_int_cst_lt (step1, step))
129 : {
130 329525 : incr_op = (incr_op == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR);
131 : step = step1;
132 : }
133 : }
134 : else
135 : {
136 1948 : bool ovf;
137 :
138 1948 : if (!tree_expr_nonnegative_warnv_p (step, &ovf)
139 1948 : && may_negate_without_overflow_p (step))
140 : {
141 21 : incr_op = (incr_op == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR);
142 21 : step = fold_build1 (NEGATE_EXPR, TREE_TYPE (step), step);
143 : }
144 : }
145 : }
146 988769 : if (POINTER_TYPE_P (TREE_TYPE (base)))
147 : {
148 135063 : if (TREE_CODE (base) == ADDR_EXPR)
149 48393 : mark_addressable (TREE_OPERAND (base, 0));
150 135063 : step = convert_to_ptrofftype (step);
151 135063 : if (incr_op == MINUS_EXPR)
152 2969 : step = fold_build1 (NEGATE_EXPR, TREE_TYPE (step), step);
153 : incr_op = POINTER_PLUS_EXPR;
154 : }
155 : /* Gimplify the step if necessary. We put the computations in front of the
156 : loop (i.e. the step should be loop invariant). */
157 988769 : step = force_gimple_operand (step, &stmts, true, NULL_TREE);
158 988769 : if (stmts)
159 0 : gsi_insert_seq_on_edge_immediate (pe, stmts);
160 :
161 988769 : gimple_seq incr_stmts = nullptr;
162 988769 : gimple_seq_add_stmt (&incr_stmts,
163 988769 : gimple_build_assign (va, incr_op, vb, step));
164 988769 : insert_iv_increment (incr_pos, after, incr_stmts);
165 :
166 988769 : initial = force_gimple_operand (base, &stmts, true, var);
167 988769 : if (stmts)
168 254803 : gsi_insert_seq_on_edge_immediate (pe, stmts);
169 :
170 988769 : phi = create_phi_node (vb, loop->header);
171 988769 : add_phi_arg (phi, initial, loop_preheader_edge (loop), UNKNOWN_LOCATION);
172 988769 : add_phi_arg (phi, va, loop_latch_edge (loop), UNKNOWN_LOCATION);
173 988769 : }
174 :
175 : /* Return the innermost superloop LOOP of USE_LOOP that is a superloop of
176 : both DEF_LOOP and USE_LOOP. */
177 :
178 : static inline class loop *
179 144901 : find_sibling_superloop (class loop *use_loop, class loop *def_loop)
180 : {
181 144901 : unsigned ud = loop_depth (use_loop);
182 144901 : unsigned dd = loop_depth (def_loop);
183 144901 : gcc_assert (ud > 0 && dd > 0);
184 144901 : if (ud > dd)
185 18788 : use_loop = superloop_at_depth (use_loop, dd);
186 144901 : if (ud < dd)
187 25551 : def_loop = superloop_at_depth (def_loop, ud);
188 147410 : while (loop_outer (use_loop) != loop_outer (def_loop))
189 : {
190 2509 : use_loop = loop_outer (use_loop);
191 2509 : def_loop = loop_outer (def_loop);
192 2509 : gcc_assert (use_loop && def_loop);
193 : }
194 144901 : return use_loop;
195 : }
196 :
197 : /* DEF_BB is a basic block containing a DEF that needs rewriting into
198 : loop-closed SSA form. USE_BLOCKS is the set of basic blocks containing
199 : uses of DEF that "escape" from the loop containing DEF_BB (i.e. blocks in
200 : USE_BLOCKS are dominated by DEF_BB but not in the loop father of DEF_BB).
201 : ALL_EXITS[I] is the set of all basic blocks that exit loop I.
202 : DEF_LOOP_EXITS is a bitmap of loop exit blocks that exit the loop
203 : containing DEF_BB or its outer loops.
204 :
205 : Compute the subset of loop exit destinations that exit the loop
206 : containing DEF_BB or one of its loop fathers, in which DEF is live.
207 : This set is returned in the bitmap LIVE_EXITS.
208 :
209 : Instead of computing the complete livein set of the def, we use the loop
210 : nesting tree as a form of poor man's structure analysis. This greatly
211 : speeds up the analysis, which is important because this function may be
212 : called on all SSA names that need rewriting, one at a time. */
213 :
214 : static void
215 3133585 : compute_live_loop_exits (bitmap live_exits, bitmap use_blocks,
216 : basic_block def_bb, bitmap def_loop_exits)
217 : {
218 3133585 : unsigned i;
219 3133585 : bitmap_iterator bi;
220 3133585 : class loop *def_loop = def_bb->loop_father;
221 3133585 : unsigned def_loop_depth = loop_depth (def_loop);
222 :
223 : /* Normally the work list size is bounded by the number of basic
224 : blocks in the largest loop. We don't know this number, but we
225 : can be fairly sure that it will be relatively small. */
226 3133585 : auto_vec<basic_block, 8> worklist (MAX (8, n_basic_blocks_for_fn (cfun) / 128));
227 :
228 7567019 : EXECUTE_IF_SET_IN_BITMAP (use_blocks, 0, i, bi)
229 : {
230 4433434 : basic_block use_bb = BASIC_BLOCK_FOR_FN (cfun, i);
231 4433434 : class loop *use_loop = use_bb->loop_father;
232 4433434 : gcc_checking_assert (def_loop != use_loop
233 : && ! flow_loop_nested_p (def_loop, use_loop));
234 4433434 : if (! flow_loop_nested_p (use_loop, def_loop))
235 122584 : use_bb = find_sibling_superloop (use_loop, def_loop)->header;
236 4433434 : if (bitmap_set_bit (live_exits, use_bb->index))
237 4392145 : worklist.safe_push (use_bb);
238 : }
239 :
240 : /* Iterate until the worklist is empty. */
241 9703666 : while (! worklist.is_empty ())
242 : {
243 6570081 : edge e;
244 6570081 : edge_iterator ei;
245 :
246 : /* Pull a block off the worklist. */
247 6570081 : basic_block bb = worklist.pop ();
248 :
249 : /* Make sure we have at least enough room in the work list
250 : for all predecessors of this block. */
251 6570081 : worklist.reserve (EDGE_COUNT (bb->preds));
252 :
253 : /* For each predecessor block. */
254 14161429 : FOR_EACH_EDGE (e, ei, bb->preds)
255 : {
256 7591348 : basic_block pred = e->src;
257 7591348 : class loop *pred_loop = pred->loop_father;
258 7591348 : unsigned pred_loop_depth = loop_depth (pred_loop);
259 7591348 : bool pred_visited;
260 :
261 : /* We should have met DEF_BB along the way. */
262 7591348 : gcc_assert (pred != ENTRY_BLOCK_PTR_FOR_FN (cfun));
263 :
264 7591348 : if (pred_loop_depth >= def_loop_depth)
265 : {
266 4634861 : if (pred_loop_depth > def_loop_depth)
267 149909 : pred_loop = superloop_at_depth (pred_loop, def_loop_depth);
268 : /* If we've reached DEF_LOOP, our train ends here. */
269 4634861 : if (pred_loop == def_loop)
270 5413412 : continue;
271 : }
272 2956487 : else if (! flow_loop_nested_p (pred_loop, def_loop))
273 22317 : pred = find_sibling_superloop (pred_loop, def_loop)->header;
274 :
275 : /* Add PRED to the LIVEIN set. PRED_VISITED is true if
276 : we had already added PRED to LIVEIN before. */
277 3790056 : pred_visited = !bitmap_set_bit (live_exits, pred->index);
278 :
279 : /* If we have visited PRED before, don't add it to the worklist.
280 : If BB dominates PRED, then we're probably looking at a loop.
281 : We're only interested in looking up in the dominance tree
282 : because DEF_BB dominates all the uses. */
283 3790056 : if (pred_visited || dominated_by_p (CDI_DOMINATORS, pred, bb))
284 1612120 : continue;
285 :
286 2177936 : worklist.quick_push (pred);
287 : }
288 : }
289 :
290 3133585 : bitmap_and_into (live_exits, def_loop_exits);
291 3133585 : }
292 :
293 : /* Add a loop-closing PHI for VAR in basic block EXIT. */
294 :
295 : static void
296 3732076 : add_exit_phi (basic_block exit, tree var)
297 : {
298 3732076 : gphi *phi;
299 3732076 : edge e;
300 3732076 : edge_iterator ei;
301 :
302 : /* Check that at least one of the edges entering the EXIT block exits
303 : the loop, or a superloop of that loop, that VAR is defined in. */
304 3732076 : if (flag_checking)
305 : {
306 3731972 : gimple *def_stmt = SSA_NAME_DEF_STMT (var);
307 3731972 : basic_block def_bb = gimple_bb (def_stmt);
308 3741576 : FOR_EACH_EDGE (e, ei, exit->preds)
309 : {
310 7483152 : class loop *aloop = find_common_loop (def_bb->loop_father,
311 3741576 : e->src->loop_father);
312 3741576 : if (!flow_bb_inside_loop_p (aloop, e->dest))
313 : break;
314 : }
315 3731972 : gcc_assert (e);
316 : }
317 :
318 3732076 : phi = create_phi_node (NULL_TREE, exit);
319 3732076 : create_new_def_for (var, phi, gimple_phi_result_ptr (phi));
320 7655667 : FOR_EACH_EDGE (e, ei, exit->preds)
321 3923591 : add_phi_arg (phi, var, e, UNKNOWN_LOCATION);
322 :
323 3732076 : if (dump_file && (dump_flags & TDF_DETAILS))
324 : {
325 1901 : fprintf (dump_file, ";; Created LCSSA PHI: ");
326 1901 : print_gimple_stmt (dump_file, phi, 0, dump_flags);
327 : }
328 3732076 : }
329 :
330 : /* Add exit phis for VAR that is used in LIVEIN.
331 : Exits of the loops are stored in LOOP_EXITS. Returns the number
332 : of PHIs added for VAR. */
333 :
334 : static unsigned
335 3133585 : add_exit_phis_var (tree var, bitmap use_blocks, bitmap def_loop_exits)
336 : {
337 3133585 : unsigned index;
338 3133585 : bitmap_iterator bi;
339 3133585 : basic_block def_bb = gimple_bb (SSA_NAME_DEF_STMT (var));
340 :
341 3133585 : gcc_checking_assert (! bitmap_bit_p (use_blocks, def_bb->index));
342 :
343 3133585 : auto_bitmap live_exits (&loop_renamer_obstack);
344 3133585 : compute_live_loop_exits (live_exits, use_blocks, def_bb, def_loop_exits);
345 :
346 3133585 : unsigned cnt = 0;
347 6865661 : EXECUTE_IF_SET_IN_BITMAP (live_exits, 0, index, bi)
348 : {
349 3732076 : add_exit_phi (BASIC_BLOCK_FOR_FN (cfun, index), var);
350 3732076 : cnt++;
351 : }
352 3133585 : return cnt;
353 3133585 : }
354 :
355 : static int
356 46861815 : loop_name_cmp (const void *p1, const void *p2)
357 : {
358 46861815 : auto l1 = (const std::pair<int, int> *)p1;
359 46861815 : auto l2 = (const std::pair<int, int> *)p2;
360 46861815 : if (l1->first < l2->first)
361 : return -1;
362 28232410 : else if (l1->first > l2->first)
363 17541886 : return 1;
364 : return 0;
365 : }
366 :
367 : /* Add exit phis for the names marked in NAMES_TO_RENAME.
368 : Exits of the loops are stored in EXITS. Sets of blocks where the ssa
369 : names are used are stored in USE_BLOCKS. Returns whether any name
370 : required multiple LC PHI nodes. */
371 :
372 : static bool
373 720614 : add_exit_phis (bitmap names_to_rename, bitmap *use_blocks)
374 : {
375 720614 : unsigned i;
376 720614 : bitmap_iterator bi;
377 720614 : bool multiple_p = false;
378 :
379 : /* Sort names_to_rename after definition loop so we can avoid re-computing
380 : def_loop_exits. */
381 720614 : auto_vec<std::pair<int, int> > names (bitmap_count_bits (names_to_rename));
382 3854199 : EXECUTE_IF_SET_IN_BITMAP (names_to_rename, 0, i, bi)
383 : {
384 3133585 : tree name = ssa_name (i);
385 3133585 : loop_p def_loop = gimple_bb (SSA_NAME_DEF_STMT (name))->loop_father;
386 3133585 : names.quick_push (std::make_pair (def_loop->num, i));
387 : }
388 720614 : names.qsort (loop_name_cmp);
389 :
390 720614 : auto_bitmap def_loop_exits (&loop_renamer_obstack);
391 720614 : loop_p last_def_loop = NULL;
392 5295427 : for (auto p : names)
393 : {
394 3133585 : loop_p def_loop = get_loop (cfun, p.first);
395 3133585 : if (def_loop != last_def_loop)
396 : {
397 1729992 : bitmap_clear (def_loop_exits);
398 1729992 : last_def_loop = def_loop;
399 4049452 : for (class loop *loop = def_loop; loop != current_loops->tree_root;
400 2319460 : loop = loop_outer (loop))
401 8297230 : for (auto exit = loop->exits->next; exit->e; exit = exit->next)
402 5977770 : bitmap_set_bit (def_loop_exits, exit->e->dest->index);
403 : }
404 3133585 : if (add_exit_phis_var (ssa_name (p.second), use_blocks[p.second],
405 : def_loop_exits) > 1)
406 354916 : multiple_p = true;
407 : }
408 :
409 720614 : return multiple_p;
410 720614 : }
411 :
412 : /* For USE in BB, if it is used outside of the loop it is defined in,
413 : mark it for rewrite. Record basic block BB where it is used
414 : to USE_BLOCKS. Record the ssa name index to NEED_PHIS bitmap.
415 : Note that for USEs in phis, BB should be the src of the edge corresponding to
416 : the use, rather than the bb containing the phi. */
417 :
418 : static void
419 162605519 : find_uses_to_rename_use (basic_block bb, tree use, bitmap *use_blocks,
420 : bitmap need_phis)
421 : {
422 162605519 : unsigned ver;
423 162605519 : basic_block def_bb;
424 162605519 : class loop *def_loop;
425 :
426 162605519 : if (TREE_CODE (use) != SSA_NAME)
427 : return;
428 :
429 156729525 : ver = SSA_NAME_VERSION (use);
430 156729525 : def_bb = gimple_bb (SSA_NAME_DEF_STMT (use));
431 156729525 : if (!def_bb)
432 : return;
433 145366367 : def_loop = def_bb->loop_father;
434 :
435 : /* If the definition is not inside a loop, it is not interesting. */
436 145366367 : if (!loop_outer (def_loop))
437 : return;
438 :
439 : /* If the use is not outside of the loop it is defined in, it is not
440 : interesting. */
441 75878365 : if (flow_bb_inside_loop_p (def_loop, bb))
442 : return;
443 :
444 : /* If we're seeing VER for the first time, we still have to allocate
445 : a bitmap for its uses. */
446 5063090 : if (bitmap_set_bit (need_phis, ver))
447 3133585 : use_blocks[ver] = BITMAP_ALLOC (&loop_renamer_obstack);
448 5063090 : bitmap_set_bit (use_blocks[ver], bb->index);
449 : }
450 :
451 : /* For uses matching USE_FLAGS in STMT, mark names that are used outside of the
452 : loop they are defined to rewrite. Record the set of blocks in which the ssa
453 : names are used to USE_BLOCKS, and the ssa names themselves to NEED_PHIS. */
454 :
455 : static void
456 210589399 : find_uses_to_rename_stmt (gimple *stmt, bitmap *use_blocks, bitmap need_phis,
457 : int use_flags)
458 : {
459 210589399 : ssa_op_iter iter;
460 210589399 : tree var;
461 210589399 : basic_block bb = gimple_bb (stmt);
462 :
463 210589399 : if (is_gimple_debug (stmt))
464 122444145 : return;
465 :
466 : /* FOR_EACH_SSA_TREE_OPERAND iterator does not allows SSA_OP_VIRTUAL_USES
467 : only. */
468 88145254 : if (use_flags == SSA_OP_VIRTUAL_USES)
469 : {
470 88145254 : tree vuse = gimple_vuse (stmt);
471 0 : if (vuse != NULL_TREE)
472 0 : find_uses_to_rename_use (bb, gimple_vuse (stmt), use_blocks, need_phis);
473 : }
474 : else
475 213303879 : FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, use_flags)
476 125158625 : find_uses_to_rename_use (bb, var, use_blocks, need_phis);
477 : }
478 :
479 : /* Marks names matching USE_FLAGS that are used in BB and outside of the loop
480 : they are defined in for rewrite. Records the set of blocks in which the ssa
481 : names are used to USE_BLOCKS. Record the SSA names that will
482 : need exit PHIs in NEED_PHIS. */
483 :
484 : static void
485 30287715 : find_uses_to_rename_bb (basic_block bb, bitmap *use_blocks, bitmap need_phis,
486 : int use_flags)
487 : {
488 30287715 : edge e;
489 30287715 : edge_iterator ei;
490 30287715 : bool do_virtuals = (use_flags & SSA_OP_VIRTUAL_USES) != 0;
491 30287715 : bool do_nonvirtuals = (use_flags & SSA_OP_USE) != 0;
492 :
493 73427994 : FOR_EACH_EDGE (e, ei, bb->succs)
494 80587173 : for (gphi_iterator bsi = gsi_start_phis (e->dest); !gsi_end_p (bsi);
495 37446894 : gsi_next (&bsi))
496 : {
497 37446894 : gphi *phi = bsi.phi ();
498 37446894 : bool virtual_p = virtual_operand_p (gimple_phi_result (phi));
499 37446894 : if ((virtual_p && do_virtuals)
500 22376635 : || (!virtual_p && do_nonvirtuals))
501 37446894 : find_uses_to_rename_use (bb, PHI_ARG_DEF_FROM_EDGE (phi, e),
502 : use_blocks, need_phis);
503 : }
504 :
505 271164829 : for (gimple_stmt_iterator bsi = gsi_start_bb (bb); !gsi_end_p (bsi);
506 210589399 : gsi_next (&bsi))
507 210589399 : find_uses_to_rename_stmt (gsi_stmt (bsi), use_blocks, need_phis,
508 : use_flags);
509 30287715 : }
510 :
511 : /* Marks names matching USE_FLAGS that are used outside of the loop they are
512 : defined in for rewrite. Records the set of blocks in which the ssa names are
513 : used to USE_BLOCKS. Record the SSA names that will need exit PHIs in
514 : NEED_PHIS. If CHANGED_BBS is not NULL, scan only blocks in this set. */
515 :
516 : static void
517 1039056 : find_uses_to_rename (bitmap changed_bbs, bitmap *use_blocks, bitmap need_phis,
518 : int use_flags)
519 : {
520 1039056 : basic_block bb;
521 1039056 : unsigned index;
522 1039056 : bitmap_iterator bi;
523 :
524 1039056 : if (changed_bbs)
525 27714 : EXECUTE_IF_SET_IN_BITMAP (changed_bbs, 0, index, bi)
526 : {
527 20236 : bb = BASIC_BLOCK_FOR_FN (cfun, index);
528 20236 : if (bb)
529 20236 : find_uses_to_rename_bb (bb, use_blocks, need_phis, use_flags);
530 : }
531 : else
532 31299057 : FOR_EACH_BB_FN (bb, cfun)
533 30267479 : find_uses_to_rename_bb (bb, use_blocks, need_phis, use_flags);
534 1039056 : }
535 :
536 : /* Rewrites the program into a loop closed ssa form -- i.e. inserts extra
537 : phi nodes to ensure that no variable is used outside the loop it is
538 : defined in.
539 :
540 : This strengthening of the basic ssa form has several advantages:
541 :
542 : 1) Updating it during unrolling/peeling/versioning is trivial, since
543 : we do not need to care about the uses outside of the loop.
544 : The same applies to virtual operands which are also rewritten into
545 : loop closed SSA form. Note that virtual operands are always live
546 : until function exit.
547 : 2) The behavior of all uses of an induction variable is the same.
548 : Without this, you need to distinguish the case when the variable
549 : is used outside of the loop it is defined in, for example
550 :
551 : for (i = 0; i < 100; i++)
552 : {
553 : for (j = 0; j < 100; j++)
554 : {
555 : k = i + j;
556 : use1 (k);
557 : }
558 : use2 (k);
559 : }
560 :
561 : Looking from the outer loop with the normal SSA form, the first use of k
562 : is not well-behaved, while the second one is an induction variable with
563 : base 99 and step 1.
564 :
565 : If CHANGED_BBS is not NULL, we look for uses outside loops only in the
566 : basic blocks in this set.
567 :
568 : USE_FLAGS allows us to specify whether we want virtual, non-virtual or
569 : both variables rewritten.
570 :
571 : UPDATE_FLAG is used in the call to update_ssa. See
572 : TODO_update_ssa* for documentation. */
573 :
574 : static void
575 4569706 : rewrite_into_loop_closed_ssa_1 (bitmap changed_bbs, unsigned update_flag,
576 : int use_flags)
577 : {
578 4569706 : bitmap *use_blocks;
579 4569706 : bitmap names_to_rename;
580 :
581 4569706 : loops_state_set (LOOP_CLOSED_SSA);
582 4569706 : if (number_of_loops (cfun) <= 1)
583 : return;
584 :
585 : /* If the pass has caused the SSA form to be out-of-date, update it
586 : now. */
587 1039056 : if (update_flag != 0)
588 1038678 : update_ssa (update_flag);
589 378 : else if (flag_checking)
590 378 : verify_ssa (true, true);
591 :
592 1039056 : bitmap_obstack_initialize (&loop_renamer_obstack);
593 :
594 1039056 : names_to_rename = BITMAP_ALLOC (&loop_renamer_obstack);
595 :
596 : /* Uses of names to rename. We don't have to initialize this array,
597 : because we know that we will only have entries for the SSA names
598 : in NAMES_TO_RENAME. */
599 2078112 : use_blocks = XNEWVEC (bitmap, num_ssa_names);
600 1039056 : find_uses_to_rename (changed_bbs, use_blocks, names_to_rename, use_flags);
601 :
602 1039056 : if (!bitmap_empty_p (names_to_rename))
603 : {
604 720614 : bool release_recorded_exits_p = false;
605 720614 : if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS))
606 : {
607 : /* Doing one scan over the whole function is cheaper than
608 : traversing the loop tree and gathering BBs of each loop. */
609 0 : record_loop_exits ();
610 0 : release_recorded_exits_p = true;
611 : }
612 :
613 : /* Add the PHI nodes on exits of the loops for the names we need to
614 : rewrite. When no variable required multiple LC PHI nodes to be
615 : inserted then we know that all uses outside of the loop are
616 : dominated by the single LC SSA definition and no further PHI
617 : node insertions are required. */
618 720614 : bool need_phis_p = add_exit_phis (names_to_rename, use_blocks);
619 :
620 720614 : if (release_recorded_exits_p)
621 0 : release_recorded_exits (cfun);
622 :
623 : /* Fix up all the names found to be used outside their original
624 : loops. */
625 1295602 : update_ssa (need_phis_p ? TODO_update_ssa : TODO_update_ssa_no_phi);
626 : }
627 :
628 1039056 : bitmap_obstack_release (&loop_renamer_obstack);
629 1039056 : free (use_blocks);
630 : }
631 :
632 : /* Rewrites the defs and uses into a loop closed ssa form.
633 : If CHANGED_BBS is not NULL, we look for uses outside loops only in the basic
634 : blocks in this set. UPDATE_FLAG is used in the call to update_ssa. See
635 : TODO_update_ssa* for documentation. */
636 :
637 : void
638 4569706 : rewrite_into_loop_closed_ssa (bitmap changed_bbs, unsigned update_flag)
639 : {
640 4569706 : rewrite_into_loop_closed_ssa_1 (changed_bbs, update_flag, SSA_OP_ALL_USES);
641 4569706 : }
642 :
643 : /* Check invariants of the loop closed ssa form for the def in DEF_BB. */
644 :
645 : static void
646 173631958 : check_loop_closed_ssa_def (basic_block def_bb, tree def)
647 : {
648 173631958 : use_operand_p use_p;
649 173631958 : imm_use_iterator iterator;
650 685799903 : FOR_EACH_IMM_USE_FAST (use_p, iterator, def)
651 : {
652 338535987 : if (is_gimple_debug (USE_STMT (use_p)))
653 44419823 : continue;
654 :
655 294116164 : basic_block use_bb = gimple_bb (USE_STMT (use_p));
656 294116164 : if (is_a <gphi *> (USE_STMT (use_p)))
657 79584724 : use_bb = EDGE_PRED (use_bb, PHI_ARG_INDEX_FROM_USE (use_p))->src;
658 :
659 294116164 : gcc_assert (flow_bb_inside_loop_p (def_bb->loop_father, use_bb));
660 173631958 : }
661 173631958 : }
662 :
663 : /* Checks invariants of loop closed ssa form in BB. */
664 :
665 : static void
666 51105414 : check_loop_closed_ssa_bb (basic_block bb)
667 : {
668 93178685 : for (gphi_iterator bsi = gsi_start_phis (bb); !gsi_end_p (bsi);
669 42073271 : gsi_next (&bsi))
670 : {
671 42073271 : gphi *phi = bsi.phi ();
672 :
673 42073271 : check_loop_closed_ssa_def (bb, PHI_RESULT (phi));
674 : }
675 :
676 206586894 : for (gimple_stmt_iterator bsi = gsi_start_nondebug_bb (bb); !gsi_end_p (bsi);
677 155481480 : gsi_next_nondebug (&bsi))
678 : {
679 155481480 : ssa_op_iter iter;
680 155481480 : tree var;
681 155481480 : gimple *stmt = gsi_stmt (bsi);
682 :
683 287040167 : FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_ALL_DEFS)
684 131558687 : check_loop_closed_ssa_def (bb, var);
685 : }
686 51105414 : }
687 :
688 : /* Checks that invariants of the loop closed ssa form are preserved.
689 : Call verify_ssa when VERIFY_SSA_P is true. Note all loops are checked
690 : if LOOP is NULL, otherwise, only LOOP is checked. */
691 :
692 : DEBUG_FUNCTION void
693 3900359 : verify_loop_closed_ssa (bool verify_ssa_p, class loop *loop)
694 : {
695 7800718 : if (number_of_loops (cfun) <= 1)
696 : return;
697 :
698 3900359 : timevar_push (TV_VERIFY_LOOP_CLOSED);
699 :
700 3900359 : if (loop == NULL)
701 : {
702 3898775 : basic_block bb;
703 :
704 3898775 : if (verify_ssa_p)
705 33482 : verify_ssa (false, true);
706 :
707 129564196 : FOR_EACH_BB_FN (bb, cfun)
708 125665421 : if (bb->loop_father && bb->loop_father->num > 0)
709 51097804 : check_loop_closed_ssa_bb (bb);
710 : }
711 : else
712 : {
713 1584 : basic_block *bbs = get_loop_body (loop);
714 :
715 : /* We do not have loop-local SSA verification so just
716 : check there's no update queued. */
717 1584 : if (verify_ssa_p)
718 1584 : gcc_assert (!need_ssa_update_p (cfun));
719 :
720 9194 : for (unsigned i = 0; i < loop->num_nodes; ++i)
721 7610 : check_loop_closed_ssa_bb (bbs[i]);
722 :
723 1584 : free (bbs);
724 : }
725 :
726 3900359 : timevar_pop (TV_VERIFY_LOOP_CLOSED);
727 : }
728 :
729 : /* Split loop exit edge EXIT. The things are a bit complicated by a need to
730 : preserve the loop closed ssa form. If COPY_CONSTANTS_P is true then
731 : forwarder PHIs are also created for constant arguments.
732 : The newly created block is returned. */
733 :
734 : basic_block
735 66590 : split_loop_exit_edge (edge exit, bool copy_constants_p)
736 : {
737 66590 : basic_block dest = exit->dest;
738 66590 : basic_block bb = split_edge (exit);
739 66590 : gphi *phi, *new_phi;
740 66590 : tree new_name, name;
741 66590 : use_operand_p op_p;
742 66590 : gphi_iterator psi;
743 66590 : location_t locus;
744 :
745 159763 : for (psi = gsi_start_phis (dest); !gsi_end_p (psi); gsi_next (&psi))
746 : {
747 93173 : phi = psi.phi ();
748 93173 : op_p = PHI_ARG_DEF_PTR_FROM_EDGE (phi, single_succ_edge (bb));
749 93173 : locus = gimple_phi_arg_location_from_edge (phi, single_succ_edge (bb));
750 :
751 93173 : name = USE_FROM_PTR (op_p);
752 :
753 : /* If the argument of the PHI node is a constant, we do not need
754 : to keep it inside loop. */
755 93173 : if (TREE_CODE (name) != SSA_NAME
756 3137 : && !copy_constants_p)
757 3002 : continue;
758 :
759 : /* Otherwise create an auxiliary phi node that will copy the value
760 : of the SSA name out of the loop. */
761 90171 : new_name = duplicate_ssa_name (PHI_RESULT (phi), NULL);
762 90171 : new_phi = create_phi_node (new_name, bb);
763 90171 : add_phi_arg (new_phi, name, exit, locus);
764 90171 : SET_USE (op_p, new_name);
765 : }
766 :
767 66590 : return bb;
768 : }
769 :
770 : /* Returns the basic block in that statements should be emitted for induction
771 : variables incremented at the end of the LOOP. */
772 :
773 : basic_block
774 24042318 : ip_end_pos (class loop *loop)
775 : {
776 24042318 : return loop->latch;
777 : }
778 :
779 : /* Returns the basic block in that statements should be emitted for induction
780 : variables incremented just before exit condition of a LOOP. */
781 :
782 : basic_block
783 49917541 : ip_normal_pos (class loop *loop)
784 : {
785 49917541 : basic_block bb;
786 49917541 : edge exit;
787 :
788 49968267 : if (!single_pred_p (loop->latch))
789 : return NULL;
790 :
791 49774755 : bb = single_pred (loop->latch);
792 99730606 : if (!safe_is_a <gcond *> (*gsi_last_bb (bb)))
793 : return NULL;
794 :
795 49762339 : exit = EDGE_SUCC (bb, 0);
796 49762339 : if (exit->dest == loop->latch)
797 37789603 : exit = EDGE_SUCC (bb, 1);
798 :
799 49762339 : if (flow_bb_inside_loop_p (loop, exit->dest))
800 : return NULL;
801 :
802 : return bb;
803 : }
804 :
805 : /* Stores the standard position for induction variable increment in LOOP
806 : (just before the exit condition if it is available and latch block is empty,
807 : end of the latch block otherwise) to BSI. INSERT_AFTER is set to true if
808 : the increment should be inserted after *BSI. */
809 :
810 : void
811 150315 : standard_iv_increment_position (class loop *loop, gimple_stmt_iterator *bsi,
812 : bool *insert_after)
813 : {
814 150315 : basic_block bb = ip_normal_pos (loop), latch = ip_end_pos (loop);
815 150315 : gimple *last = last_nondebug_stmt (latch);
816 :
817 150315 : if (!bb
818 150315 : || (last && gimple_code (last) != GIMPLE_LABEL))
819 : {
820 39 : *bsi = gsi_last_bb (latch);
821 39 : *insert_after = true;
822 : }
823 : else
824 : {
825 150276 : *bsi = gsi_last_bb (bb);
826 150276 : *insert_after = false;
827 : }
828 150315 : }
829 :
830 : /* Copies phi node arguments for duplicated blocks. The index of the first
831 : duplicated block is FIRST_NEW_BLOCK. */
832 :
833 : static void
834 145959 : copy_phi_node_args (unsigned first_new_block)
835 : {
836 145959 : unsigned i;
837 :
838 1271318 : for (i = first_new_block; i < (unsigned) last_basic_block_for_fn (cfun); i++)
839 1125359 : BASIC_BLOCK_FOR_FN (cfun, i)->flags |= BB_DUPLICATED;
840 :
841 1271318 : for (i = first_new_block; i < (unsigned) last_basic_block_for_fn (cfun); i++)
842 1125359 : add_phi_args_after_copy_bb (BASIC_BLOCK_FOR_FN (cfun, i));
843 :
844 1271318 : for (i = first_new_block; i < (unsigned) last_basic_block_for_fn (cfun); i++)
845 1125359 : BASIC_BLOCK_FOR_FN (cfun, i)->flags &= ~BB_DUPLICATED;
846 145959 : }
847 :
848 :
849 : /* The same as cfgloopmanip.cc:duplicate_loop_body_to_header_edge, but also
850 : updates the PHI nodes at start of the copied region. In order to
851 : achieve this, only loops whose exits all lead to the same location
852 : are handled.
853 :
854 : Notice that we do not completely update the SSA web after
855 : duplication. The caller is responsible for calling update_ssa
856 : after the loop has been duplicated. */
857 :
858 : bool
859 145978 : gimple_duplicate_loop_body_to_header_edge (class loop *loop, edge e,
860 : unsigned int ndupl,
861 : sbitmap wont_exit, edge orig,
862 : vec<edge> *to_remove, int flags)
863 : {
864 145978 : unsigned first_new_block;
865 :
866 145978 : if (!loops_state_satisfies_p (LOOPS_HAVE_SIMPLE_LATCHES))
867 : return false;
868 145978 : if (!loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS))
869 : return false;
870 :
871 145978 : first_new_block = last_basic_block_for_fn (cfun);
872 145978 : if (!duplicate_loop_body_to_header_edge (loop, e, ndupl, wont_exit, orig,
873 : to_remove, flags))
874 : return false;
875 :
876 : /* Readd the removed phi args for e. */
877 145959 : flush_pending_stmts (e);
878 :
879 : /* Copy the phi node arguments. */
880 145959 : copy_phi_node_args (first_new_block);
881 :
882 145959 : scev_reset ();
883 :
884 145959 : return true;
885 : }
886 :
887 : /* Returns true if we can unroll LOOP FACTOR times. Number
888 : of iterations of the loop is returned in NITER. */
889 :
890 : bool
891 847 : can_unroll_loop_p (class loop *loop, unsigned factor,
892 : class tree_niter_desc *niter)
893 : {
894 847 : edge exit;
895 :
896 : /* Check whether unrolling is possible. We only want to unroll loops
897 : for that we are able to determine number of iterations. We also
898 : want to split the extra iterations of the loop from its end,
899 : therefore we require that the loop has precisely one
900 : exit. */
901 :
902 847 : exit = single_dom_exit (loop);
903 847 : if (!exit)
904 : return false;
905 :
906 826 : if (!number_of_iterations_exit (loop, exit, niter, false)
907 825 : || niter->cmp == ERROR_MARK
908 : /* Scalar evolutions analysis might have copy propagated
909 : the abnormal ssa names into these expressions, hence
910 : emitting the computations based on them during loop
911 : unrolling might create overlapping life ranges for
912 : them, and failures in out-of-ssa. */
913 823 : || contains_abnormal_ssa_name_p (niter->may_be_zero)
914 823 : || contains_abnormal_ssa_name_p (niter->control.base)
915 823 : || contains_abnormal_ssa_name_p (niter->control.step)
916 1649 : || contains_abnormal_ssa_name_p (niter->bound))
917 3 : return false;
918 :
919 : /* And of course, we must be able to duplicate the loop. */
920 823 : if (!can_duplicate_loop_p (loop))
921 : return false;
922 :
923 : /* The final loop should be small enough. */
924 823 : if (tree_num_loop_insns (loop, &eni_size_weights) * factor
925 823 : > (unsigned) param_max_unrolled_insns)
926 : return false;
927 :
928 : return true;
929 : }
930 :
931 : /* Determines the conditions that control execution of LOOP unrolled FACTOR
932 : times. DESC is number of iterations of LOOP. ENTER_COND is set to
933 : condition that must be true if the main loop can be entered.
934 : If the loop does not always iterate an exact multiple of FACTOR times,
935 : EXIT_BASE, EXIT_STEP, EXIT_CMP and EXIT_BOUND are set to values describing
936 : how the exit from the unrolled loop should be controlled. Otherwise,
937 : the trees are set to null and EXIT_CMP is set to ERROR_MARK. */
938 :
939 : static void
940 807 : determine_exit_conditions (class loop *loop, class tree_niter_desc *desc,
941 : unsigned factor, tree *enter_cond,
942 : tree *exit_base, tree *exit_step,
943 : enum tree_code *exit_cmp, tree *exit_bound)
944 : {
945 807 : gimple_seq stmts;
946 807 : tree base = desc->control.base;
947 807 : tree step = desc->control.step;
948 807 : tree bound = desc->bound;
949 807 : tree type = TREE_TYPE (step);
950 807 : tree bigstep, delta;
951 807 : tree min = lower_bound_in_type (type, type);
952 807 : tree max = upper_bound_in_type (type, type);
953 807 : enum tree_code cmp = desc->cmp;
954 807 : tree cond = boolean_true_node, assum;
955 :
956 : /* For pointers, do the arithmetics in the type of step. */
957 807 : base = fold_convert (type, base);
958 807 : bound = fold_convert (type, bound);
959 :
960 807 : *enter_cond = boolean_false_node;
961 807 : *exit_base = NULL_TREE;
962 807 : *exit_step = NULL_TREE;
963 807 : *exit_cmp = ERROR_MARK;
964 807 : *exit_bound = NULL_TREE;
965 807 : gcc_assert (cmp != ERROR_MARK);
966 :
967 : /* We only need to be correct when we answer question
968 : "Do at least FACTOR more iterations remain?" in the unrolled loop.
969 : Thus, transforming BASE + STEP * i <> BOUND to
970 : BASE + STEP * i < BOUND is ok. */
971 807 : if (cmp == NE_EXPR)
972 : {
973 84 : if (tree_int_cst_sign_bit (step))
974 : cmp = GT_EXPR;
975 : else
976 759 : cmp = LT_EXPR;
977 : }
978 723 : else if (cmp == LT_EXPR)
979 : {
980 721 : gcc_assert (!tree_int_cst_sign_bit (step));
981 : }
982 2 : else if (cmp == GT_EXPR)
983 : {
984 2 : gcc_assert (tree_int_cst_sign_bit (step));
985 : }
986 : else
987 0 : gcc_unreachable ();
988 :
989 : /* The main body of the loop may be entered iff:
990 :
991 : 1) desc->may_be_zero is false.
992 : 2) it is possible to check that there are at least FACTOR iterations
993 : of the loop, i.e., BOUND - step * FACTOR does not overflow.
994 : 3) # of iterations is at least FACTOR */
995 :
996 807 : if (!integer_zerop (desc->may_be_zero))
997 6 : cond = fold_build2 (TRUTH_AND_EXPR, boolean_type_node,
998 : invert_truthvalue (desc->may_be_zero),
999 : cond);
1000 :
1001 807 : bigstep = fold_build2 (MULT_EXPR, type, step,
1002 : build_int_cst_type (type, factor));
1003 807 : delta = fold_build2 (MINUS_EXPR, type, bigstep, step);
1004 807 : if (cmp == LT_EXPR)
1005 759 : assum = fold_build2 (GE_EXPR, boolean_type_node,
1006 : bound,
1007 : fold_build2 (PLUS_EXPR, type, min, delta));
1008 : else
1009 48 : assum = fold_build2 (LE_EXPR, boolean_type_node,
1010 : bound,
1011 : fold_build2 (PLUS_EXPR, type, max, delta));
1012 807 : cond = fold_build2 (TRUTH_AND_EXPR, boolean_type_node, assum, cond);
1013 :
1014 807 : bound = fold_build2 (MINUS_EXPR, type, bound, delta);
1015 807 : assum = fold_build2 (cmp, boolean_type_node, base, bound);
1016 807 : cond = fold_build2 (TRUTH_AND_EXPR, boolean_type_node, assum, cond);
1017 :
1018 807 : if (integer_nonzerop (cond)
1019 807 : && integer_zerop (desc->may_be_zero))
1020 : {
1021 : /* Convert the latch count to an iteration count. */
1022 77 : tree niter = fold_build2 (PLUS_EXPR, type, desc->niter,
1023 : build_one_cst (type));
1024 77 : if (multiple_of_p (type, niter, build_int_cst (type, factor)))
1025 30 : return;
1026 : }
1027 :
1028 777 : cond = force_gimple_operand (unshare_expr (cond), &stmts, false, NULL_TREE);
1029 777 : if (stmts)
1030 17 : gsi_insert_seq_on_edge_immediate (loop_preheader_edge (loop), stmts);
1031 : /* cond now may be a gimple comparison, which would be OK, but also any
1032 : other gimple rhs (say a && b). In this case we need to force it to
1033 : operand. */
1034 777 : if (!is_gimple_condexpr_for_cond (cond))
1035 : {
1036 14 : cond = force_gimple_operand (cond, &stmts, true, NULL_TREE);
1037 14 : if (stmts)
1038 14 : gsi_insert_seq_on_edge_immediate (loop_preheader_edge (loop), stmts);
1039 : }
1040 777 : *enter_cond = cond;
1041 :
1042 777 : base = force_gimple_operand (unshare_expr (base), &stmts, true, NULL_TREE);
1043 777 : if (stmts)
1044 29 : gsi_insert_seq_on_edge_immediate (loop_preheader_edge (loop), stmts);
1045 777 : bound = force_gimple_operand (unshare_expr (bound), &stmts, true, NULL_TREE);
1046 777 : if (stmts)
1047 697 : gsi_insert_seq_on_edge_immediate (loop_preheader_edge (loop), stmts);
1048 :
1049 777 : *exit_base = base;
1050 777 : *exit_step = bigstep;
1051 777 : *exit_cmp = cmp;
1052 777 : *exit_bound = bound;
1053 : }
1054 :
1055 : /* Unroll LOOP FACTOR times. LOOP is known to have a single exit edge
1056 : whose source block dominates the latch. DESC describes the number of
1057 : iterations of LOOP.
1058 :
1059 : If N is number of iterations of the loop and MAY_BE_ZERO is the condition
1060 : under that loop exits in the first iteration even if N != 0,
1061 :
1062 : while (1)
1063 : {
1064 : x = phi (init, next);
1065 :
1066 : pre;
1067 : if (st)
1068 : break;
1069 : post;
1070 : }
1071 :
1072 : becomes (with possibly the exit conditions formulated a bit differently,
1073 : avoiding the need to create a new iv):
1074 :
1075 : if (MAY_BE_ZERO || N < FACTOR)
1076 : goto rest;
1077 :
1078 : do
1079 : {
1080 : x = phi (init, next);
1081 :
1082 : pre;
1083 : post;
1084 : pre;
1085 : post;
1086 : ...
1087 : pre;
1088 : post;
1089 : N -= FACTOR;
1090 :
1091 : } while (N >= FACTOR);
1092 :
1093 : rest:
1094 : init' = phi (init, x);
1095 :
1096 : while (1)
1097 : {
1098 : x = phi (init', next);
1099 :
1100 : pre;
1101 : if (st)
1102 : break;
1103 : post;
1104 : }
1105 :
1106 : Before the loop is unrolled, TRANSFORM is called for it (only for the
1107 : unrolled loop, but not for its versioned copy). DATA is passed to
1108 : TRANSFORM. */
1109 :
1110 : /* Probability in % that the unrolled loop is entered. Just a guess. */
1111 : #define PROB_UNROLLED_LOOP_ENTERED 90
1112 :
1113 : void
1114 807 : tree_transform_and_unroll_loop (class loop *loop, unsigned factor,
1115 : class tree_niter_desc *desc,
1116 : transform_callback transform,
1117 : void *data)
1118 : {
1119 807 : unsigned irr = loop_preheader_edge (loop)->flags & EDGE_IRREDUCIBLE_LOOP;
1120 :
1121 807 : enum tree_code exit_cmp;
1122 807 : tree enter_main_cond, exit_base, exit_step, exit_bound;
1123 807 : bool flat = maybe_flat_loop_profile (loop);
1124 807 : determine_exit_conditions (loop, desc, factor,
1125 : &enter_main_cond, &exit_base, &exit_step,
1126 : &exit_cmp, &exit_bound);
1127 807 : bool single_loop_p = !exit_base;
1128 :
1129 807 : gcond *exit_if = nullptr;
1130 807 : class loop *new_loop = nullptr;
1131 807 : edge new_exit;
1132 807 : if (!single_loop_p)
1133 : {
1134 777 : profile_count entry_count = loop_preheader_edge (loop)->src->count;
1135 : /* Let us assume that the unrolled loop is quite likely to be entered. */
1136 777 : profile_probability prob_entry;
1137 777 : if (integer_nonzerop (enter_main_cond))
1138 47 : prob_entry = profile_probability::always ();
1139 : else
1140 730 : prob_entry = profile_probability::guessed_always ()
1141 730 : .apply_scale (PROB_UNROLLED_LOOP_ENTERED, 100);
1142 :
1143 :
1144 : /* The values for scales should keep profile consistent, and somewhat
1145 : close to correct. */
1146 777 : new_loop = loop_version (loop, enter_main_cond, NULL, prob_entry,
1147 : prob_entry.invert (),
1148 : prob_entry,
1149 : /* We will later redirect exit from vectorized
1150 : loop to new_loop. */
1151 : profile_probability::always (),
1152 : true);
1153 777 : gcc_assert (new_loop != NULL);
1154 777 : update_ssa (TODO_update_ssa_no_phi);
1155 :
1156 : /* Prepare the cfg and update the phi nodes. Move the loop exit to the
1157 : loop latch (and make its condition dummy, for the moment). */
1158 777 : basic_block rest = loop_preheader_edge (new_loop)->src;
1159 777 : edge precond_edge = single_pred_edge (rest);
1160 777 : split_edge (loop_latch_edge (loop));
1161 777 : basic_block exit_bb = single_pred (loop->latch);
1162 777 : edge exit = single_dom_exit (loop);
1163 :
1164 : /* Since the exit edge will be removed, the frequency of all the blocks
1165 : in the loop that are dominated by it must be scaled. */
1166 777 : if (exit->probability.initialized_p ())
1167 777 : scale_dominated_blocks_in_loop (loop, exit->src,
1168 : /* We are scaling up here so
1169 : probability does not fit. */
1170 777 : exit->src->count,
1171 1554 : exit->src->count - exit->count ());
1172 :
1173 777 : gimple_stmt_iterator bsi = gsi_last_bb (exit_bb);
1174 777 : exit_if = gimple_build_cond (EQ_EXPR, integer_zero_node,
1175 : integer_zero_node,
1176 : NULL_TREE, NULL_TREE);
1177 :
1178 777 : gsi_insert_after (&bsi, exit_if, GSI_NEW_STMT);
1179 777 : new_exit = make_edge (exit_bb, rest, EDGE_FALSE_VALUE | irr);
1180 777 : rescan_loop_exit (new_exit, true, false);
1181 :
1182 : /* Set the probability of new exit to the same of the old one. Fix
1183 : the count of the latch block. */
1184 777 : new_exit->probability = exit->probability;
1185 777 : edge new_nonexit = single_pred_edge (loop->latch);
1186 777 : new_nonexit->probability = exit->probability.invert ();
1187 777 : new_nonexit->flags = EDGE_TRUE_VALUE;
1188 777 : set_edge_probability_and_rescale_others
1189 777 : (exit, profile_probability::never ());
1190 777 : loop->latch->count = new_nonexit->count ();
1191 :
1192 777 : edge old_entry = loop_preheader_edge (loop);
1193 777 : edge new_entry = loop_preheader_edge (new_loop);
1194 777 : edge old_latch = loop_latch_edge (loop);
1195 777 : for (gphi_iterator psi_old_loop = gsi_start_phis (loop->header),
1196 777 : psi_new_loop = gsi_start_phis (new_loop->header);
1197 2424 : !gsi_end_p (psi_old_loop);
1198 1647 : gsi_next (&psi_old_loop), gsi_next (&psi_new_loop))
1199 : {
1200 1647 : gphi *phi_old_loop = psi_old_loop.phi ();
1201 1647 : gphi *phi_new_loop = psi_new_loop.phi ();
1202 :
1203 1647 : tree init = PHI_ARG_DEF_FROM_EDGE (phi_old_loop, old_entry);
1204 1647 : use_operand_p op
1205 1647 : = PHI_ARG_DEF_PTR_FROM_EDGE (phi_new_loop, new_entry);
1206 1647 : gcc_assert (operand_equal_for_phi_arg_p (init, USE_FROM_PTR (op)));
1207 1647 : tree next = PHI_ARG_DEF_FROM_EDGE (phi_old_loop, old_latch);
1208 :
1209 : /* Prefer using original variable as a base for the new ssa name.
1210 : This is necessary for virtual ops, and useful in order to avoid
1211 : losing debug info for real ops. */
1212 1647 : tree new_init;
1213 1647 : if (TREE_CODE (next) == SSA_NAME
1214 3294 : && useless_type_conversion_p (TREE_TYPE (next),
1215 1647 : TREE_TYPE (init)))
1216 1647 : new_init = copy_ssa_name (next);
1217 0 : else if (TREE_CODE (init) == SSA_NAME
1218 0 : && useless_type_conversion_p (TREE_TYPE (init),
1219 0 : TREE_TYPE (next)))
1220 0 : new_init = copy_ssa_name (init);
1221 0 : else if (useless_type_conversion_p (TREE_TYPE (next),
1222 0 : TREE_TYPE (init)))
1223 0 : new_init = make_temp_ssa_name (TREE_TYPE (next), NULL,
1224 : "unrinittmp");
1225 : else
1226 0 : new_init = make_temp_ssa_name (TREE_TYPE (init), NULL,
1227 : "unrinittmp");
1228 :
1229 1647 : gphi *phi_rest = create_phi_node (new_init, rest);
1230 1647 : add_phi_arg (phi_rest, init, precond_edge, UNKNOWN_LOCATION);
1231 1647 : add_phi_arg (phi_rest, next, new_exit, UNKNOWN_LOCATION);
1232 1647 : SET_USE (op, new_init);
1233 : }
1234 :
1235 777 : remove_path (exit);
1236 : /* We will later redirect exit from vectorized loop to new_loop. */
1237 777 : loop_preheader_edge (new_loop)->src->count = entry_count;
1238 :
1239 : /* The epilog loop latch executes at most factor - 1 times.
1240 : Since the epilog is entered unconditionally it will need to handle
1241 : up to factor executions of its body. */
1242 777 : new_loop->any_upper_bound = true;
1243 777 : new_loop->nb_iterations_upper_bound = factor - 1;
1244 : /* We do not really know estimate on number of iterations, since we do not
1245 : track any estimates modulo unroll factor.
1246 : Drop estimate from loop_info and scale loop profile.
1247 : It may be more realistic to scale loop profile to factor / 2 - 1,
1248 : but vectorizer also uses factor - 1. */
1249 777 : new_loop->any_estimate = false;
1250 777 : scale_loop_profile (new_loop, profile_probability::always (), factor - 1);
1251 : }
1252 : else
1253 30 : new_exit = single_dom_exit (loop);
1254 :
1255 : /* Transform the loop. */
1256 807 : if (transform)
1257 716 : (*transform) (loop, data);
1258 :
1259 : /* Unroll the loop and remove the exits in all iterations except for the
1260 : last one. */
1261 807 : auto_sbitmap wont_exit (factor);
1262 807 : bitmap_ones (wont_exit);
1263 807 : bitmap_clear_bit (wont_exit, factor - 1);
1264 :
1265 807 : auto_vec<edge> to_remove;
1266 807 : bool ok
1267 : = gimple_duplicate_loop_body_to_header_edge
1268 879 : (loop, loop_latch_edge (loop), factor - 1, wont_exit,
1269 : new_exit, &to_remove,
1270 : DLTHE_FLAG_UPDATE_FREQ | (flat ? DLTHE_FLAG_FLAT_PROFILE : 0));
1271 807 : gcc_assert (ok);
1272 :
1273 3475 : for (edge e : to_remove)
1274 : {
1275 1054 : ok = remove_path (e);
1276 1054 : gcc_assert (ok);
1277 : }
1278 807 : update_ssa (TODO_update_ssa);
1279 :
1280 807 : new_exit = single_dom_exit (loop);
1281 : /* gimple_duplicate_loop_body_to_header_edge depending on
1282 : DLTHE_FLAG_UPDATE_FREQ either keeps original frequency of the loop header
1283 : or scales it down accordingly.
1284 : However exit edge probability is kept as original. Fix it if needed
1285 : and compensate. */
1286 807 : update_loop_exit_probability_scale_dom_bbs (loop, new_exit);
1287 807 : if (!single_loop_p)
1288 : {
1289 : /* Finally create the new counter for number of iterations and add
1290 : the new exit instruction. */
1291 777 : tree ctr_before, ctr_after;
1292 777 : gimple_stmt_iterator bsi = gsi_last_nondebug_bb (new_exit->src);
1293 777 : exit_if = as_a <gcond *> (gsi_stmt (bsi));
1294 777 : create_iv (exit_base, PLUS_EXPR, exit_step, NULL_TREE, loop,
1295 : &bsi, false, &ctr_before, &ctr_after);
1296 777 : gimple_cond_set_code (exit_if, exit_cmp);
1297 777 : gimple_cond_set_lhs (exit_if, ctr_after);
1298 777 : gimple_cond_set_rhs (exit_if, exit_bound);
1299 777 : update_stmt (exit_if);
1300 : }
1301 807 : if (loop->any_upper_bound)
1302 1592 : loop->nb_iterations_upper_bound = wi::udiv_floor
1303 796 : (loop->nb_iterations_upper_bound + 1, factor) - 1;
1304 807 : if (loop->any_likely_upper_bound)
1305 1592 : loop->nb_iterations_likely_upper_bound = wi::udiv_floor
1306 796 : (loop->nb_iterations_likely_upper_bound + 1, factor) - 1;
1307 807 : if (loop->any_estimate)
1308 172 : loop->nb_iterations_estimate = wi::udiv_floor
1309 86 : (loop->nb_iterations_estimate + 1, factor) - 1;
1310 :
1311 807 : checking_verify_flow_info ();
1312 807 : checking_verify_loop_structure ();
1313 807 : checking_verify_loop_closed_ssa (true, loop);
1314 807 : if (new_loop)
1315 1584 : checking_verify_loop_closed_ssa (true, new_loop);
1316 807 : }
1317 :
1318 : /* Wrapper over tree_transform_and_unroll_loop for case we do not
1319 : want to transform the loop before unrolling. The meaning
1320 : of the arguments is the same as for tree_transform_and_unroll_loop. */
1321 :
1322 : void
1323 91 : tree_unroll_loop (class loop *loop, unsigned factor,
1324 : class tree_niter_desc *desc)
1325 : {
1326 91 : tree_transform_and_unroll_loop (loop, factor, desc, NULL, NULL);
1327 91 : }
1328 :
1329 : /* Rewrite the phi node at position PSI in function of the main
1330 : induction variable MAIN_IV and insert the generated code at GSI. */
1331 :
1332 : static void
1333 2038 : rewrite_phi_with_iv (loop_p loop,
1334 : gphi_iterator *psi,
1335 : gimple_stmt_iterator *gsi,
1336 : tree main_iv)
1337 : {
1338 2038 : affine_iv iv;
1339 2038 : gassign *stmt;
1340 2038 : gphi *phi = psi->phi ();
1341 2038 : tree atype, mtype, val, res = PHI_RESULT (phi);
1342 :
1343 4076 : if (virtual_operand_p (res) || res == main_iv)
1344 : {
1345 1160 : gsi_next (psi);
1346 1243 : return;
1347 : }
1348 :
1349 878 : if (!simple_iv (loop, loop, res, &iv, true))
1350 : {
1351 83 : gsi_next (psi);
1352 83 : return;
1353 : }
1354 :
1355 795 : remove_phi_node (psi, false);
1356 :
1357 795 : atype = TREE_TYPE (res);
1358 795 : mtype = POINTER_TYPE_P (atype) ? sizetype : atype;
1359 795 : val = fold_build2 (MULT_EXPR, mtype, unshare_expr (iv.step),
1360 : fold_convert (mtype, main_iv));
1361 1588 : val = fold_build2 (POINTER_TYPE_P (atype)
1362 : ? POINTER_PLUS_EXPR : PLUS_EXPR,
1363 : atype, unshare_expr (iv.base), val);
1364 795 : val = force_gimple_operand_gsi (gsi, val, false, NULL_TREE, true,
1365 : GSI_SAME_STMT);
1366 795 : stmt = gimple_build_assign (res, val);
1367 795 : gsi_insert_before (gsi, stmt, GSI_SAME_STMT);
1368 : }
1369 :
1370 : /* Rewrite all the phi nodes of LOOP in function of the main induction
1371 : variable MAIN_IV. */
1372 :
1373 : static void
1374 583 : rewrite_all_phi_nodes_with_iv (loop_p loop, tree main_iv)
1375 : {
1376 583 : unsigned i;
1377 583 : basic_block *bbs = get_loop_body_in_dom_order (loop);
1378 583 : gphi_iterator psi;
1379 :
1380 2064 : for (i = 0; i < loop->num_nodes; i++)
1381 : {
1382 1481 : basic_block bb = bbs[i];
1383 1481 : gimple_stmt_iterator gsi = gsi_after_labels (bb);
1384 :
1385 1481 : if (bb->loop_father != loop)
1386 97 : continue;
1387 :
1388 3422 : for (psi = gsi_start_phis (bb); !gsi_end_p (psi); )
1389 2038 : rewrite_phi_with_iv (loop, &psi, &gsi, main_iv);
1390 : }
1391 :
1392 583 : free (bbs);
1393 583 : }
1394 :
1395 : /* Bases all the induction variables in LOOP on a single induction variable
1396 : (with base 0 and step 1), whose final value is compared with *NIT. When the
1397 : IV type precision has to be larger than *NIT type precision, *NIT is
1398 : converted to the larger type, the conversion code is inserted before the
1399 : loop, and *NIT is updated to the new definition. When BUMP_IN_LATCH is true,
1400 : the induction variable is incremented in the loop latch, otherwise it is
1401 : incremented in the loop header. Return the induction variable that was
1402 : created. */
1403 :
1404 : tree
1405 583 : canonicalize_loop_ivs (class loop *loop, tree *nit, bool bump_in_latch)
1406 : {
1407 583 : unsigned precision = TYPE_PRECISION (TREE_TYPE (*nit));
1408 583 : unsigned original_precision = precision;
1409 583 : tree type, var_before;
1410 583 : gimple_stmt_iterator gsi;
1411 583 : gphi_iterator psi;
1412 583 : gcond *stmt;
1413 583 : edge exit = single_dom_exit (loop);
1414 583 : gimple_seq stmts;
1415 583 : bool unsigned_p = false;
1416 :
1417 583 : for (psi = gsi_start_phis (loop->header);
1418 1934 : !gsi_end_p (psi); gsi_next (&psi))
1419 : {
1420 1351 : gphi *phi = psi.phi ();
1421 1351 : tree res = PHI_RESULT (phi);
1422 1351 : bool uns;
1423 :
1424 1351 : type = TREE_TYPE (res);
1425 1351 : if (virtual_operand_p (res)
1426 857 : || (!INTEGRAL_TYPE_P (type)
1427 21 : && !POINTER_TYPE_P (type))
1428 2193 : || TYPE_PRECISION (type) < precision)
1429 531 : continue;
1430 :
1431 820 : uns = POINTER_TYPE_P (type) | TYPE_UNSIGNED (type);
1432 :
1433 820 : if (TYPE_PRECISION (type) > precision)
1434 : unsigned_p = uns;
1435 : else
1436 815 : unsigned_p |= uns;
1437 :
1438 820 : precision = TYPE_PRECISION (type);
1439 : }
1440 :
1441 583 : scalar_int_mode mode = smallest_int_mode_for_size (precision).require ();
1442 583 : precision = GET_MODE_PRECISION (mode);
1443 583 : type = build_nonstandard_integer_type (precision, unsigned_p);
1444 :
1445 583 : if (original_precision != precision
1446 583 : || TYPE_UNSIGNED (TREE_TYPE (*nit)) != unsigned_p)
1447 : {
1448 301 : *nit = fold_convert (type, *nit);
1449 301 : *nit = force_gimple_operand (*nit, &stmts, true, NULL_TREE);
1450 301 : if (stmts)
1451 115 : gsi_insert_seq_on_edge_immediate (loop_preheader_edge (loop), stmts);
1452 : }
1453 :
1454 583 : if (bump_in_latch)
1455 1166 : gsi = gsi_last_bb (loop->latch);
1456 : else
1457 0 : gsi = gsi_last_nondebug_bb (loop->header);
1458 583 : create_iv (build_int_cst_type (type, 0), PLUS_EXPR, build_int_cst (type, 1),
1459 : NULL_TREE, loop, &gsi, bump_in_latch, &var_before, NULL);
1460 :
1461 583 : rewrite_all_phi_nodes_with_iv (loop, var_before);
1462 :
1463 1166 : stmt = as_a <gcond *> (*gsi_last_bb (exit->src));
1464 : /* Make the loop exit if the control condition is not satisfied. */
1465 583 : if (exit->flags & EDGE_TRUE_VALUE)
1466 : {
1467 100 : edge te, fe;
1468 :
1469 100 : extract_true_false_edges_from_block (exit->src, &te, &fe);
1470 100 : te->flags = EDGE_FALSE_VALUE;
1471 100 : fe->flags = EDGE_TRUE_VALUE;
1472 : }
1473 583 : gimple_cond_set_code (stmt, LT_EXPR);
1474 583 : gimple_cond_set_lhs (stmt, var_before);
1475 583 : gimple_cond_set_rhs (stmt, *nit);
1476 583 : update_stmt (stmt);
1477 :
1478 583 : return var_before;
1479 : }
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