Line data Source code
1 : /* Functions to determine/estimate number of iterations of a loop.
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 "rtl.h"
25 : #include "tree.h"
26 : #include "gimple.h"
27 : #include "tree-pass.h"
28 : #include "ssa.h"
29 : #include "gimple-pretty-print.h"
30 : #include "diagnostic-core.h"
31 : #include "stor-layout.h"
32 : #include "fold-const.h"
33 : #include "calls.h"
34 : #include "intl.h"
35 : #include "gimple-iterator.h"
36 : #include "tree-cfg.h"
37 : #include "tree-ssa-loop-ivopts.h"
38 : #include "tree-ssa-loop-niter.h"
39 : #include "tree-ssa-loop.h"
40 : #include "cfgloop.h"
41 : #include "tree-chrec.h"
42 : #include "tree-scalar-evolution.h"
43 : #include "tree-data-ref.h"
44 : #include "tree-dfa.h"
45 : #include "internal-fn.h"
46 : #include "gimple-range.h"
47 : #include "sreal.h"
48 :
49 :
50 : /*
51 :
52 : Analysis of number of iterations of an affine exit test.
53 :
54 : */
55 :
56 : /* Bounds on some value, BELOW <= X <= UP. */
57 :
58 : struct bounds
59 : {
60 : mpz_t below, up;
61 : };
62 :
63 : /* Splits expression EXPR to a variable part VAR and constant OFFSET. */
64 :
65 : static void
66 57325432 : split_to_var_and_offset (tree expr, tree *var, mpz_t offset)
67 : {
68 57325432 : tree type = TREE_TYPE (expr);
69 57325432 : tree op0, op1;
70 57325432 : bool negate = false;
71 :
72 57325432 : *var = expr;
73 57325432 : mpz_set_ui (offset, 0);
74 :
75 57325432 : switch (TREE_CODE (expr))
76 : {
77 8088 : case MINUS_EXPR:
78 8088 : negate = true;
79 : /* Fallthru. */
80 :
81 5832362 : case PLUS_EXPR:
82 5832362 : case POINTER_PLUS_EXPR:
83 5832362 : op0 = TREE_OPERAND (expr, 0);
84 5832362 : op1 = TREE_OPERAND (expr, 1);
85 :
86 5832362 : if (TREE_CODE (op1) != INTEGER_CST)
87 : break;
88 :
89 5820953 : *var = op0;
90 : /* Always sign extend the offset. */
91 5820953 : wi::to_mpz (wi::to_wide (op1), offset, SIGNED);
92 5820953 : if (negate)
93 34 : mpz_neg (offset, offset);
94 : break;
95 :
96 25424845 : case INTEGER_CST:
97 25424845 : *var = build_int_cst_type (type, 0);
98 25424845 : wi::to_mpz (wi::to_wide (expr), offset, TYPE_SIGN (type));
99 25424845 : break;
100 :
101 : default:
102 : break;
103 : }
104 57325432 : }
105 :
106 : /* From condition C0 CMP C1 derives information regarding the value range
107 : of VAR, which is of TYPE. Results are stored in to BELOW and UP. */
108 :
109 : static void
110 20668213 : refine_value_range_using_guard (tree type, tree var,
111 : tree c0, enum tree_code cmp, tree c1,
112 : mpz_t below, mpz_t up)
113 : {
114 20668213 : tree varc0, varc1, ctype;
115 20668213 : mpz_t offc0, offc1;
116 20668213 : mpz_t mint, maxt, minc1, maxc1;
117 20668213 : bool no_wrap = nowrap_type_p (type);
118 20668213 : bool c0_ok, c1_ok;
119 20668213 : signop sgn = TYPE_SIGN (type);
120 :
121 20668213 : switch (cmp)
122 : {
123 9718743 : case LT_EXPR:
124 9718743 : case LE_EXPR:
125 9718743 : case GT_EXPR:
126 9718743 : case GE_EXPR:
127 9718743 : STRIP_SIGN_NOPS (c0);
128 9718743 : STRIP_SIGN_NOPS (c1);
129 9718743 : ctype = TREE_TYPE (c0);
130 9718743 : if (!useless_type_conversion_p (ctype, type))
131 17690774 : return;
132 :
133 : break;
134 :
135 : case EQ_EXPR:
136 : /* We could derive quite precise information from EQ_EXPR, however,
137 : such a guard is unlikely to appear, so we do not bother with
138 : handling it. */
139 : return;
140 :
141 5045437 : case NE_EXPR:
142 : /* NE_EXPR comparisons do not contain much of useful information,
143 : except for cases of comparing with bounds. */
144 5045437 : if (TREE_CODE (c1) != INTEGER_CST
145 4726725 : || !INTEGRAL_TYPE_P (type))
146 : return;
147 :
148 : /* Ensure that the condition speaks about an expression in the same
149 : type as X and Y. */
150 4726725 : ctype = TREE_TYPE (c0);
151 4726725 : if (TYPE_PRECISION (ctype) != TYPE_PRECISION (type))
152 : return;
153 2878511 : c0 = fold_convert (type, c0);
154 2878511 : c1 = fold_convert (type, c1);
155 :
156 2878511 : if (operand_equal_p (var, c0, 0))
157 : {
158 : /* Case of comparing VAR with its below/up bounds. */
159 303420 : auto_mpz valc1;
160 303420 : wi::to_mpz (wi::to_wide (c1), valc1, TYPE_SIGN (type));
161 303420 : if (mpz_cmp (valc1, below) == 0)
162 100525 : cmp = GT_EXPR;
163 303420 : if (mpz_cmp (valc1, up) == 0)
164 46868 : cmp = LT_EXPR;
165 303420 : }
166 : else
167 : {
168 : /* Case of comparing with the bounds of the type. */
169 2575091 : wide_int min = wi::min_value (type);
170 2575091 : wide_int max = wi::max_value (type);
171 :
172 2575091 : if (wi::to_wide (c1) == min)
173 715058 : cmp = GT_EXPR;
174 2575091 : if (wi::to_wide (c1) == max)
175 28323 : cmp = LT_EXPR;
176 2575091 : }
177 :
178 : /* Quick return if no useful information. */
179 2878511 : if (cmp == NE_EXPR)
180 : return;
181 :
182 : break;
183 :
184 : default:
185 : return;
186 : }
187 :
188 8990097 : mpz_init (offc0);
189 8990097 : mpz_init (offc1);
190 8990097 : split_to_var_and_offset (expand_simple_operations (c0), &varc0, offc0);
191 8990097 : split_to_var_and_offset (expand_simple_operations (c1), &varc1, offc1);
192 :
193 : /* We are only interested in comparisons of expressions based on VAR. */
194 8990097 : if (operand_equal_p (var, varc1, 0))
195 : {
196 864139 : std::swap (varc0, varc1);
197 864139 : mpz_swap (offc0, offc1);
198 864139 : cmp = swap_tree_comparison (cmp);
199 : }
200 8125958 : else if (!operand_equal_p (var, varc0, 0))
201 : {
202 6012658 : mpz_clear (offc0);
203 6012658 : mpz_clear (offc1);
204 6012658 : return;
205 : }
206 :
207 2977439 : mpz_init (mint);
208 2977439 : mpz_init (maxt);
209 2977439 : get_type_static_bounds (type, mint, maxt);
210 2977439 : mpz_init (minc1);
211 2977439 : mpz_init (maxc1);
212 5954878 : int_range_max r (TREE_TYPE (varc1));
213 : /* Setup range information for varc1. */
214 2977439 : if (integer_zerop (varc1))
215 : {
216 1474513 : wi::to_mpz (0, minc1, TYPE_SIGN (type));
217 1474513 : wi::to_mpz (0, maxc1, TYPE_SIGN (type));
218 : }
219 1502926 : else if (TREE_CODE (varc1) == SSA_NAME
220 1407971 : && INTEGRAL_TYPE_P (type)
221 2815942 : && get_range_query (cfun)->range_of_expr (r, varc1)
222 1407971 : && !r.undefined_p ()
223 2908409 : && !r.varying_p ())
224 : {
225 1491844 : gcc_assert (wi::le_p (r.lower_bound (), r.upper_bound (), sgn));
226 745922 : wi::to_mpz (r.lower_bound (), minc1, sgn);
227 745922 : wi::to_mpz (r.upper_bound (), maxc1, sgn);
228 : }
229 : else
230 : {
231 757004 : mpz_set (minc1, mint);
232 757004 : mpz_set (maxc1, maxt);
233 : }
234 :
235 : /* Compute valid range information for varc1 + offc1. Note nothing
236 : useful can be derived if it overflows or underflows. Overflow or
237 : underflow could happen when:
238 :
239 : offc1 > 0 && varc1 + offc1 > MAX_VAL (type)
240 : offc1 < 0 && varc1 + offc1 < MIN_VAL (type). */
241 2977439 : mpz_add (minc1, minc1, offc1);
242 2977439 : mpz_add (maxc1, maxc1, offc1);
243 5954878 : c1_ok = (no_wrap
244 858039 : || mpz_sgn (offc1) == 0
245 165213 : || (mpz_sgn (offc1) < 0 && mpz_cmp (minc1, mint) >= 0)
246 3141194 : || (mpz_sgn (offc1) > 0 && mpz_cmp (maxc1, maxt) <= 0));
247 27593 : if (!c1_ok)
248 27593 : goto end;
249 :
250 2949846 : if (mpz_cmp (minc1, mint) < 0)
251 28550 : mpz_set (minc1, mint);
252 2949846 : if (mpz_cmp (maxc1, maxt) > 0)
253 16484 : mpz_set (maxc1, maxt);
254 :
255 2949846 : if (cmp == LT_EXPR)
256 : {
257 404648 : cmp = LE_EXPR;
258 404648 : mpz_sub_ui (maxc1, maxc1, 1);
259 : }
260 2949846 : if (cmp == GT_EXPR)
261 : {
262 1533078 : cmp = GE_EXPR;
263 1533078 : mpz_add_ui (minc1, minc1, 1);
264 : }
265 :
266 : /* Compute range information for varc0. If there is no overflow,
267 : the condition implied that
268 :
269 : (varc0) cmp (varc1 + offc1 - offc0)
270 :
271 : We can possibly improve the upper bound of varc0 if cmp is LE_EXPR,
272 : or the below bound if cmp is GE_EXPR.
273 :
274 : To prove there is no overflow/underflow, we need to check below
275 : four cases:
276 : 1) cmp == LE_EXPR && offc0 > 0
277 :
278 : (varc0 + offc0) doesn't overflow
279 : && (varc1 + offc1 - offc0) doesn't underflow
280 :
281 : 2) cmp == LE_EXPR && offc0 < 0
282 :
283 : (varc0 + offc0) doesn't underflow
284 : && (varc1 + offc1 - offc0) doesn't overfloe
285 :
286 : In this case, (varc0 + offc0) will never underflow if we can
287 : prove (varc1 + offc1 - offc0) doesn't overflow.
288 :
289 : 3) cmp == GE_EXPR && offc0 < 0
290 :
291 : (varc0 + offc0) doesn't underflow
292 : && (varc1 + offc1 - offc0) doesn't overflow
293 :
294 : 4) cmp == GE_EXPR && offc0 > 0
295 :
296 : (varc0 + offc0) doesn't overflow
297 : && (varc1 + offc1 - offc0) doesn't underflow
298 :
299 : In this case, (varc0 + offc0) will never overflow if we can
300 : prove (varc1 + offc1 - offc0) doesn't underflow.
301 :
302 : Note we only handle case 2 and 4 in below code. */
303 :
304 2949846 : mpz_sub (minc1, minc1, offc0);
305 2949846 : mpz_sub (maxc1, maxc1, offc0);
306 5899692 : c0_ok = (no_wrap
307 830446 : || mpz_sgn (offc0) == 0
308 49160 : || (cmp == LE_EXPR
309 31417 : && mpz_sgn (offc0) < 0 && mpz_cmp (maxc1, maxt) <= 0)
310 2996489 : || (cmp == GE_EXPR
311 17743 : && mpz_sgn (offc0) > 0 && mpz_cmp (minc1, mint) >= 0));
312 44403 : if (!c0_ok)
313 44403 : goto end;
314 :
315 2905443 : if (cmp == LE_EXPR)
316 : {
317 1091813 : if (mpz_cmp (up, maxc1) > 0)
318 339003 : mpz_set (up, maxc1);
319 : }
320 : else
321 : {
322 1813630 : if (mpz_cmp (below, minc1) < 0)
323 1181779 : mpz_set (below, minc1);
324 : }
325 :
326 631851 : end:
327 2977439 : mpz_clear (mint);
328 2977439 : mpz_clear (maxt);
329 2977439 : mpz_clear (minc1);
330 2977439 : mpz_clear (maxc1);
331 2977439 : mpz_clear (offc0);
332 2977439 : mpz_clear (offc1);
333 : }
334 :
335 : /* Stores estimates of the minimum and maximum values of the expression
336 : VAR + OFF in TYPE to MIN and MAX. The estimates are valid on entry
337 : to LOOP, i.e. on the loop preheader edge. */
338 :
339 : static void
340 24973906 : determine_value_range (class loop *loop, tree type, tree var, mpz_t off,
341 : mpz_t min, mpz_t max)
342 : {
343 24973906 : int cnt = 0;
344 24973906 : mpz_t minm, maxm;
345 24973906 : basic_block bb;
346 24973906 : wide_int minv, maxv;
347 24973906 : enum value_range_kind rtype = VR_VARYING;
348 :
349 : /* If the expression is a constant, we know its value exactly. */
350 24973906 : if (integer_zerop (var))
351 : {
352 17661781 : mpz_set (min, off);
353 17661781 : mpz_set (max, off);
354 17661781 : return;
355 : }
356 :
357 7312125 : get_type_static_bounds (type, min, max);
358 :
359 : /* See if we have some range info from VRP. */
360 7312125 : if (INTEGRAL_TYPE_P (type))
361 : {
362 5891342 : edge e = loop_preheader_edge (loop);
363 5891342 : signop sgn = TYPE_SIGN (type);
364 5891342 : gphi_iterator gsi;
365 :
366 : /* Either for VAR itself... */
367 5891342 : int_range_max var_range (TREE_TYPE (var));
368 11782684 : get_range_query (cfun)->range_on_edge (var_range, e, var);
369 5891342 : if (var_range.varying_p () || var_range.undefined_p ())
370 : rtype = VR_VARYING;
371 : else
372 : rtype = VR_RANGE;
373 5891342 : if (!var_range.undefined_p ())
374 : {
375 5876264 : minv = var_range.lower_bound ();
376 5876332 : maxv = var_range.upper_bound ();
377 : }
378 :
379 : /* Or for PHI results in loop->header where VAR is used as
380 : PHI argument from the loop preheader edge. */
381 5891342 : int_range_max phi_range (TREE_TYPE (var));
382 21709713 : for (gsi = gsi_start_phis (loop->header); !gsi_end_p (gsi); gsi_next (&gsi))
383 : {
384 15818372 : gphi *phi = gsi.phi ();
385 15818372 : if (PHI_ARG_DEF_FROM_EDGE (phi, e) == var
386 2593636 : && get_range_query (cfun)->range_on_edge (phi_range,
387 : e, gimple_phi_result (phi))
388 1296818 : && !phi_range.varying_p ()
389 16559468 : && !phi_range.undefined_p ())
390 : {
391 741092 : if (rtype != VR_RANGE)
392 : {
393 253547 : rtype = VR_RANGE;
394 253547 : minv = phi_range.lower_bound ();
395 253562 : maxv = phi_range.upper_bound ();
396 : }
397 : else
398 : {
399 487547 : minv = wi::max (minv, phi_range.lower_bound (), sgn);
400 487547 : maxv = wi::min (maxv, phi_range.upper_bound (), sgn);
401 : /* If the PHI result range are inconsistent with
402 : the VAR range, give up on looking at the PHI
403 : results. This can happen if VR_UNDEFINED is
404 : involved. */
405 487545 : if (wi::gt_p (minv, maxv, sgn))
406 : {
407 1 : int_range_max vr (TREE_TYPE (var));
408 2 : get_range_query (cfun)->range_on_edge (vr, e, var);
409 1 : if (vr.varying_p () || vr.undefined_p ())
410 : rtype = VR_VARYING;
411 : else
412 : rtype = VR_RANGE;
413 1 : if (!vr.undefined_p ())
414 : {
415 1 : minv = vr.lower_bound ();
416 1 : maxv = vr.upper_bound ();
417 : }
418 1 : break;
419 1 : }
420 : }
421 : }
422 : }
423 5891342 : mpz_init (minm);
424 5891342 : mpz_init (maxm);
425 5891342 : if (rtype != VR_RANGE)
426 : {
427 2983305 : mpz_set (minm, min);
428 2983305 : mpz_set (maxm, max);
429 : }
430 : else
431 : {
432 2908037 : gcc_assert (wi::le_p (minv, maxv, sgn));
433 2908037 : wi::to_mpz (minv, minm, sgn);
434 2908037 : wi::to_mpz (maxv, maxm, sgn);
435 : }
436 : /* Now walk the dominators of the loop header and use the entry
437 : guards to refine the estimates. */
438 5891342 : for (bb = loop->header;
439 59928046 : bb != ENTRY_BLOCK_PTR_FOR_FN (cfun)
440 59928046 : && cnt < param_max_niter_dominators_walk;
441 54036704 : bb = get_immediate_dominator (CDI_DOMINATORS, bb))
442 : {
443 54036704 : edge e;
444 54036704 : tree c0, c1;
445 54036704 : enum tree_code cmp;
446 :
447 54036704 : if (!single_pred_p (bb))
448 26989928 : continue;
449 27046776 : e = single_pred_edge (bb);
450 :
451 27046776 : if (!(e->flags & (EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
452 6378563 : continue;
453 :
454 41336426 : gcond *cond = as_a <gcond *> (*gsi_last_bb (e->src));
455 20668213 : c0 = gimple_cond_lhs (cond);
456 20668213 : cmp = gimple_cond_code (cond);
457 20668213 : c1 = gimple_cond_rhs (cond);
458 :
459 20668213 : if (e->flags & EDGE_FALSE_VALUE)
460 11146833 : cmp = invert_tree_comparison (cmp, false);
461 :
462 20668213 : refine_value_range_using_guard (type, var, c0, cmp, c1, minm, maxm);
463 20668213 : ++cnt;
464 : }
465 :
466 5891342 : mpz_add (minm, minm, off);
467 5891342 : mpz_add (maxm, maxm, off);
468 : /* If the computation may not wrap or off is zero, then this
469 : is always fine. If off is negative and minv + off isn't
470 : smaller than type's minimum, or off is positive and
471 : maxv + off isn't bigger than type's maximum, use the more
472 : precise range too. */
473 5891342 : if (nowrap_type_p (type)
474 2292294 : || mpz_sgn (off) == 0
475 576784 : || (mpz_sgn (off) < 0 && mpz_cmp (minm, min) >= 0)
476 6383182 : || (mpz_sgn (off) > 0 && mpz_cmp (maxm, max) <= 0))
477 : {
478 5690175 : mpz_set (min, minm);
479 5690175 : mpz_set (max, maxm);
480 5690175 : mpz_clear (minm);
481 5690175 : mpz_clear (maxm);
482 5690175 : return;
483 : }
484 201167 : mpz_clear (minm);
485 201167 : mpz_clear (maxm);
486 5891342 : }
487 :
488 : /* If the computation may wrap, we know nothing about the value, except for
489 : the range of the type. */
490 1621950 : if (!nowrap_type_p (type))
491 : return;
492 :
493 : /* Since the addition of OFF does not wrap, if OFF is positive, then we may
494 : add it to MIN, otherwise to MAX. */
495 1420783 : if (mpz_sgn (off) < 0)
496 30093 : mpz_add (max, max, off);
497 : else
498 1390690 : mpz_add (min, min, off);
499 24973974 : }
500 :
501 : /* Stores the bounds on the difference of the values of the expressions
502 : (var + X) and (var + Y), computed in TYPE, to BNDS. */
503 :
504 : static void
505 163310 : bound_difference_of_offsetted_base (tree type, mpz_t x, mpz_t y,
506 : bounds *bnds)
507 : {
508 163310 : int rel = mpz_cmp (x, y);
509 163310 : bool may_wrap = !nowrap_type_p (type);
510 :
511 : /* If X == Y, then the expressions are always equal.
512 : If X > Y, there are the following possibilities:
513 : a) neither of var + X and var + Y overflow or underflow, or both of
514 : them do. Then their difference is X - Y.
515 : b) var + X overflows, and var + Y does not. Then the values of the
516 : expressions are var + X - M and var + Y, where M is the range of
517 : the type, and their difference is X - Y - M.
518 : c) var + Y underflows and var + X does not. Their difference again
519 : is M - X + Y.
520 : Therefore, if the arithmetics in type does not overflow, then the
521 : bounds are (X - Y, X - Y), otherwise they are (X - Y - M, X - Y)
522 : Similarly, if X < Y, the bounds are either (X - Y, X - Y) or
523 : (X - Y, X - Y + M). */
524 :
525 163310 : if (rel == 0)
526 : {
527 746 : mpz_set_ui (bnds->below, 0);
528 746 : mpz_set_ui (bnds->up, 0);
529 746 : return;
530 : }
531 :
532 162564 : auto_mpz m;
533 162564 : wi::to_mpz (wi::minus_one (TYPE_PRECISION (type)), m, UNSIGNED);
534 162564 : mpz_add_ui (m, m, 1);
535 162564 : mpz_sub (bnds->up, x, y);
536 162564 : mpz_set (bnds->below, bnds->up);
537 :
538 162564 : if (may_wrap)
539 : {
540 142030 : if (rel > 0)
541 140776 : mpz_sub (bnds->below, bnds->below, m);
542 : else
543 1254 : mpz_add (bnds->up, bnds->up, m);
544 : }
545 162564 : }
546 :
547 : /* From condition C0 CMP C1 derives information regarding the
548 : difference of values of VARX + OFFX and VARY + OFFY, computed in TYPE,
549 : and stores it to BNDS. */
550 :
551 : static void
552 19477660 : refine_bounds_using_guard (tree type, tree varx, mpz_t offx,
553 : tree vary, mpz_t offy,
554 : tree c0, enum tree_code cmp, tree c1,
555 : bounds *bnds)
556 : {
557 19477660 : tree varc0, varc1, ctype;
558 19477660 : mpz_t offc0, offc1, loffx, loffy, bnd;
559 19477660 : bool lbound = false;
560 19477660 : bool no_wrap = nowrap_type_p (type);
561 19477660 : bool x_ok, y_ok;
562 :
563 19477660 : switch (cmp)
564 : {
565 8354193 : case LT_EXPR:
566 8354193 : case LE_EXPR:
567 8354193 : case GT_EXPR:
568 8354193 : case GE_EXPR:
569 8354193 : STRIP_SIGN_NOPS (c0);
570 8354193 : STRIP_SIGN_NOPS (c1);
571 8354193 : ctype = TREE_TYPE (c0);
572 8354193 : if (!useless_type_conversion_p (ctype, type))
573 12455304 : return;
574 :
575 : break;
576 :
577 : case EQ_EXPR:
578 : /* We could derive quite precise information from EQ_EXPR, however, such
579 : a guard is unlikely to appear, so we do not bother with handling
580 : it. */
581 : return;
582 :
583 5355712 : case NE_EXPR:
584 : /* NE_EXPR comparisons do not contain much of useful information, except for
585 : special case of comparing with the bounds of the type. */
586 5355712 : if (TREE_CODE (c1) != INTEGER_CST
587 4593470 : || !INTEGRAL_TYPE_P (type))
588 : return;
589 :
590 : /* Ensure that the condition speaks about an expression in the same type
591 : as X and Y. */
592 4106005 : ctype = TREE_TYPE (c0);
593 4106005 : if (TYPE_PRECISION (ctype) != TYPE_PRECISION (type))
594 : return;
595 2356612 : c0 = fold_convert (type, c0);
596 2356612 : c1 = fold_convert (type, c1);
597 :
598 2356612 : if (TYPE_MIN_VALUE (type)
599 2356612 : && operand_equal_p (c1, TYPE_MIN_VALUE (type), 0))
600 : {
601 : cmp = GT_EXPR;
602 : break;
603 : }
604 1694913 : if (TYPE_MAX_VALUE (type)
605 1694913 : && operand_equal_p (c1, TYPE_MAX_VALUE (type), 0))
606 : {
607 : cmp = LT_EXPR;
608 : break;
609 : }
610 :
611 : return;
612 : default:
613 : return;
614 : }
615 :
616 7022356 : mpz_init (offc0);
617 7022356 : mpz_init (offc1);
618 7022356 : split_to_var_and_offset (expand_simple_operations (c0), &varc0, offc0);
619 7022356 : split_to_var_and_offset (expand_simple_operations (c1), &varc1, offc1);
620 :
621 : /* We are only interested in comparisons of expressions based on VARX and
622 : VARY. TODO -- we might also be able to derive some bounds from
623 : expressions containing just one of the variables. */
624 :
625 7022356 : if (operand_equal_p (varx, varc1, 0))
626 : {
627 955029 : std::swap (varc0, varc1);
628 955029 : mpz_swap (offc0, offc1);
629 955029 : cmp = swap_tree_comparison (cmp);
630 : }
631 :
632 7022356 : if (!operand_equal_p (varx, varc0, 0)
633 7022356 : || !operand_equal_p (vary, varc1, 0))
634 5180683 : goto end;
635 :
636 1841673 : mpz_init_set (loffx, offx);
637 1841673 : mpz_init_set (loffy, offy);
638 :
639 1841673 : if (cmp == GT_EXPR || cmp == GE_EXPR)
640 : {
641 1760855 : std::swap (varx, vary);
642 1760855 : mpz_swap (offc0, offc1);
643 1760855 : mpz_swap (loffx, loffy);
644 1760855 : cmp = swap_tree_comparison (cmp);
645 1760855 : lbound = true;
646 : }
647 :
648 : /* If there is no overflow, the condition implies that
649 :
650 : (VARX + OFFX) cmp (VARY + OFFY) + (OFFX - OFFY + OFFC1 - OFFC0).
651 :
652 : The overflows and underflows may complicate things a bit; each
653 : overflow decreases the appropriate offset by M, and underflow
654 : increases it by M. The above inequality would not necessarily be
655 : true if
656 :
657 : -- VARX + OFFX underflows and VARX + OFFC0 does not, or
658 : VARX + OFFC0 overflows, but VARX + OFFX does not.
659 : This may only happen if OFFX < OFFC0.
660 : -- VARY + OFFY overflows and VARY + OFFC1 does not, or
661 : VARY + OFFC1 underflows and VARY + OFFY does not.
662 : This may only happen if OFFY > OFFC1. */
663 :
664 1841673 : if (no_wrap)
665 : {
666 : x_ok = true;
667 : y_ok = true;
668 : }
669 : else
670 : {
671 639205 : x_ok = (integer_zerop (varx)
672 639205 : || mpz_cmp (loffx, offc0) >= 0);
673 639205 : y_ok = (integer_zerop (vary)
674 639205 : || mpz_cmp (loffy, offc1) <= 0);
675 : }
676 :
677 636322 : if (x_ok && y_ok)
678 : {
679 1835035 : mpz_init (bnd);
680 1835035 : mpz_sub (bnd, loffx, loffy);
681 1835035 : mpz_add (bnd, bnd, offc1);
682 1835035 : mpz_sub (bnd, bnd, offc0);
683 :
684 1835035 : if (cmp == LT_EXPR)
685 1490509 : mpz_sub_ui (bnd, bnd, 1);
686 :
687 1835035 : if (lbound)
688 : {
689 1755441 : mpz_neg (bnd, bnd);
690 1755441 : if (mpz_cmp (bnds->below, bnd) < 0)
691 460820 : mpz_set (bnds->below, bnd);
692 : }
693 : else
694 : {
695 79594 : if (mpz_cmp (bnd, bnds->up) < 0)
696 2904 : mpz_set (bnds->up, bnd);
697 : }
698 1835035 : mpz_clear (bnd);
699 : }
700 :
701 1841673 : mpz_clear (loffx);
702 1841673 : mpz_clear (loffy);
703 7022356 : end:
704 7022356 : mpz_clear (offc0);
705 7022356 : mpz_clear (offc1);
706 : }
707 :
708 : /* Stores the bounds on the value of the expression X - Y in LOOP to BNDS.
709 : The subtraction is considered to be performed in arbitrary precision,
710 : without overflows.
711 :
712 : We do not attempt to be too clever regarding the value ranges of X and
713 : Y; most of the time, they are just integers or ssa names offsetted by
714 : integer. However, we try to use the information contained in the
715 : comparisons before the loop (usually created by loop header copying). */
716 :
717 : static void
718 12650263 : bound_difference (class loop *loop, tree x, tree y, bounds *bnds)
719 : {
720 12650263 : tree type = TREE_TYPE (x);
721 12650263 : tree varx, vary;
722 12650263 : mpz_t offx, offy;
723 12650263 : int cnt = 0;
724 12650263 : edge e;
725 12650263 : basic_block bb;
726 12650263 : tree c0, c1;
727 12650263 : enum tree_code cmp;
728 :
729 : /* Get rid of unnecessary casts, but preserve the value of
730 : the expressions. */
731 12650263 : STRIP_SIGN_NOPS (x);
732 12650263 : STRIP_SIGN_NOPS (y);
733 :
734 12650263 : mpz_init (bnds->below);
735 12650263 : mpz_init (bnds->up);
736 12650263 : mpz_init (offx);
737 12650263 : mpz_init (offy);
738 12650263 : split_to_var_and_offset (x, &varx, offx);
739 12650263 : split_to_var_and_offset (y, &vary, offy);
740 :
741 12650263 : if (!integer_zerop (varx)
742 12650263 : && operand_equal_p (varx, vary, 0))
743 : {
744 : /* Special case VARX == VARY -- we just need to compare the
745 : offsets. The matters are a bit more complicated in the
746 : case addition of offsets may wrap. */
747 163310 : bound_difference_of_offsetted_base (type, offx, offy, bnds);
748 : }
749 : else
750 : {
751 : /* Otherwise, use the value ranges to determine the initial
752 : estimates on below and up. */
753 12486953 : auto_mpz minx, maxx, miny, maxy;
754 12486953 : determine_value_range (loop, type, varx, offx, minx, maxx);
755 12486953 : determine_value_range (loop, type, vary, offy, miny, maxy);
756 :
757 12486953 : mpz_sub (bnds->below, minx, maxy);
758 12486953 : mpz_sub (bnds->up, maxx, miny);
759 12486953 : }
760 :
761 : /* If both X and Y are constants, we cannot get any more precise. */
762 12650263 : if (integer_zerop (varx) && integer_zerop (vary))
763 7004330 : goto end;
764 :
765 : /* Now walk the dominators of the loop header and use the entry
766 : guards to refine the estimates. */
767 5645933 : for (bb = loop->header;
768 56216775 : bb != ENTRY_BLOCK_PTR_FOR_FN (cfun)
769 56216775 : && cnt < param_max_niter_dominators_walk;
770 50570842 : bb = get_immediate_dominator (CDI_DOMINATORS, bb))
771 : {
772 50570842 : if (!single_pred_p (bb))
773 24338710 : continue;
774 26232132 : e = single_pred_edge (bb);
775 :
776 26232132 : if (!(e->flags & (EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
777 6754472 : continue;
778 :
779 38955320 : gcond *cond = as_a <gcond *> (*gsi_last_bb (e->src));
780 19477660 : c0 = gimple_cond_lhs (cond);
781 19477660 : cmp = gimple_cond_code (cond);
782 19477660 : c1 = gimple_cond_rhs (cond);
783 :
784 19477660 : if (e->flags & EDGE_FALSE_VALUE)
785 10826136 : cmp = invert_tree_comparison (cmp, false);
786 :
787 19477660 : refine_bounds_using_guard (type, varx, offx, vary, offy,
788 : c0, cmp, c1, bnds);
789 19477660 : ++cnt;
790 : }
791 :
792 5645933 : end:
793 12650263 : mpz_clear (offx);
794 12650263 : mpz_clear (offy);
795 12650263 : }
796 :
797 : /* Update the bounds in BNDS that restrict the value of X to the bounds
798 : that restrict the value of X + DELTA. X can be obtained as a
799 : difference of two values in TYPE. */
800 :
801 : static void
802 2038405 : bounds_add (bounds *bnds, const widest_int &delta, tree type)
803 : {
804 2038405 : mpz_t mdelta, max;
805 :
806 2038405 : mpz_init (mdelta);
807 2038405 : wi::to_mpz (delta, mdelta, SIGNED);
808 :
809 2038405 : mpz_init (max);
810 2038405 : wi::to_mpz (wi::minus_one (TYPE_PRECISION (type)), max, UNSIGNED);
811 :
812 2038405 : mpz_add (bnds->up, bnds->up, mdelta);
813 2038405 : mpz_add (bnds->below, bnds->below, mdelta);
814 :
815 2038405 : if (mpz_cmp (bnds->up, max) > 0)
816 119055 : mpz_set (bnds->up, max);
817 :
818 2038405 : mpz_neg (max, max);
819 2038405 : if (mpz_cmp (bnds->below, max) < 0)
820 9810 : mpz_set (bnds->below, max);
821 :
822 2038405 : mpz_clear (mdelta);
823 2038405 : mpz_clear (max);
824 2038405 : }
825 :
826 : /* Update the bounds in BNDS that restrict the value of X to the bounds
827 : that restrict the value of -X. */
828 :
829 : static void
830 2496789 : bounds_negate (bounds *bnds)
831 : {
832 2496789 : mpz_t tmp;
833 :
834 2496789 : mpz_init_set (tmp, bnds->up);
835 2496789 : mpz_neg (bnds->up, bnds->below);
836 2496789 : mpz_neg (bnds->below, tmp);
837 2496789 : mpz_clear (tmp);
838 2496789 : }
839 :
840 : /* Returns inverse of X modulo 2^s, where MASK = 2^s-1. */
841 :
842 : static tree
843 173858 : inverse (tree x, tree mask)
844 : {
845 173858 : tree type = TREE_TYPE (x);
846 173858 : tree rslt;
847 173858 : unsigned ctr = tree_floor_log2 (mask);
848 :
849 173858 : if (TYPE_PRECISION (type) <= HOST_BITS_PER_WIDE_INT)
850 : {
851 173794 : unsigned HOST_WIDE_INT ix;
852 173794 : unsigned HOST_WIDE_INT imask;
853 173794 : unsigned HOST_WIDE_INT irslt = 1;
854 :
855 173794 : gcc_assert (cst_and_fits_in_hwi (x));
856 173794 : gcc_assert (cst_and_fits_in_hwi (mask));
857 :
858 173794 : ix = int_cst_value (x);
859 173794 : imask = int_cst_value (mask);
860 :
861 9902160 : for (; ctr; ctr--)
862 : {
863 9554572 : irslt *= ix;
864 9554572 : ix *= ix;
865 : }
866 173794 : irslt &= imask;
867 :
868 173794 : rslt = build_int_cst_type (type, irslt);
869 : }
870 : else
871 : {
872 64 : rslt = build_int_cst (type, 1);
873 8192 : for (; ctr; ctr--)
874 : {
875 8128 : rslt = int_const_binop (MULT_EXPR, rslt, x);
876 8128 : x = int_const_binop (MULT_EXPR, x, x);
877 : }
878 64 : rslt = int_const_binop (BIT_AND_EXPR, rslt, mask);
879 : }
880 :
881 173858 : return rslt;
882 : }
883 :
884 : /* Derives the upper bound BND on the number of executions of loop with exit
885 : condition S * i <> C. If NO_OVERFLOW is true, then the control variable of
886 : the loop does not overflow. EXIT_MUST_BE_TAKEN is true if we are guaranteed
887 : that the loop ends through this exit, i.e., the induction variable ever
888 : reaches the value of C.
889 :
890 : The value C is equal to final - base, where final and base are the final and
891 : initial value of the actual induction variable in the analysed loop. BNDS
892 : bounds the value of this difference when computed in signed type with
893 : unbounded range, while the computation of C is performed in an unsigned
894 : type with the range matching the range of the type of the induction variable.
895 : In particular, BNDS.up contains an upper bound on C in the following cases:
896 : -- if the iv must reach its final value without overflow, i.e., if
897 : NO_OVERFLOW && EXIT_MUST_BE_TAKEN is true, or
898 : -- if final >= base, which we know to hold when BNDS.below >= 0. */
899 :
900 : static void
901 7346834 : number_of_iterations_ne_max (mpz_t bnd, bool no_overflow, tree c, tree s,
902 : bounds *bnds, bool exit_must_be_taken)
903 : {
904 7346834 : widest_int max;
905 7346834 : mpz_t d;
906 7346834 : tree type = TREE_TYPE (c);
907 14693668 : bool bnds_u_valid = ((no_overflow && exit_must_be_taken)
908 7346834 : || mpz_sgn (bnds->below) >= 0);
909 :
910 7346834 : if (integer_onep (s)
911 836271 : || (TREE_CODE (c) == INTEGER_CST
912 328892 : && TREE_CODE (s) == INTEGER_CST
913 1165806 : && wi::mod_trunc (wi::to_wide (c), wi::to_wide (s),
914 8004618 : TYPE_SIGN (type)) == 0)
915 7854856 : || (TYPE_OVERFLOW_UNDEFINED (type)
916 0 : && multiple_of_p (type, c, s)))
917 : {
918 : /* If C is an exact multiple of S, then its value will be reached before
919 : the induction variable overflows (unless the loop is exited in some
920 : other way before). Note that the actual induction variable in the
921 : loop (which ranges from base to final instead of from 0 to C) may
922 : overflow, in which case BNDS.up will not be giving a correct upper
923 : bound on C; thus, BNDS_U_VALID had to be computed in advance. */
924 : no_overflow = true;
925 : exit_must_be_taken = true;
926 : }
927 :
928 : /* If the induction variable can overflow, the number of iterations is at
929 : most the period of the control variable (or infinite, but in that case
930 : the whole # of iterations analysis will fail). */
931 508022 : if (!no_overflow)
932 : {
933 121358 : max = wi::mask <widest_int> (TYPE_PRECISION (type)
934 121358 : - wi::ctz (wi::to_wide (s)), false);
935 60679 : wi::to_mpz (max, bnd, UNSIGNED);
936 60679 : return;
937 : }
938 :
939 : /* Now we know that the induction variable does not overflow, so the loop
940 : iterates at most (range of type / S) times. */
941 7286155 : wi::to_mpz (wi::minus_one (TYPE_PRECISION (type)), bnd, UNSIGNED);
942 :
943 : /* If the induction variable is guaranteed to reach the value of C before
944 : overflow, ... */
945 7286155 : if (exit_must_be_taken)
946 : {
947 : /* ... then we can strengthen this to C / S, and possibly we can use
948 : the upper bound on C given by BNDS. */
949 7045737 : if (TREE_CODE (c) == INTEGER_CST)
950 6197486 : wi::to_mpz (wi::to_wide (c), bnd, UNSIGNED);
951 848251 : else if (bnds_u_valid)
952 719279 : mpz_set (bnd, bnds->up);
953 : }
954 :
955 7286155 : mpz_init (d);
956 7286155 : wi::to_mpz (wi::to_wide (s), d, UNSIGNED);
957 7286155 : mpz_fdiv_q (bnd, bnd, d);
958 7286155 : mpz_clear (d);
959 7346834 : }
960 :
961 : /* Determines number of iterations of loop whose ending condition
962 : is IV <> FINAL. TYPE is the type of the iv. The number of
963 : iterations is stored to NITER. EXIT_MUST_BE_TAKEN is true if
964 : we know that the exit must be taken eventually, i.e., that the IV
965 : ever reaches the value FINAL (we derived this earlier, and possibly set
966 : NITER->assumptions to make sure this is the case). BNDS contains the
967 : bounds on the difference FINAL - IV->base. */
968 :
969 : static bool
970 7346834 : number_of_iterations_ne (class loop *loop, tree type, affine_iv *iv,
971 : tree final, class tree_niter_desc *niter,
972 : bool exit_must_be_taken, bounds *bnds)
973 : {
974 7346834 : tree niter_type = unsigned_type_for (type);
975 7346834 : tree s, c, d, bits, assumption, tmp, bound;
976 :
977 7346834 : niter->control = *iv;
978 7346834 : niter->bound = final;
979 7346834 : niter->cmp = NE_EXPR;
980 :
981 : /* Rearrange the terms so that we get inequality S * i <> C, with S
982 : positive. Also cast everything to the unsigned type. If IV does
983 : not overflow, BNDS bounds the value of C. Also, this is the
984 : case if the computation |FINAL - IV->base| does not overflow, i.e.,
985 : if BNDS->below in the result is nonnegative. */
986 7346834 : if (tree_int_cst_sign_bit (iv->step))
987 : {
988 2496789 : s = fold_build1 (NEGATE_EXPR, niter_type,
989 : fold_convert (niter_type, iv->step));
990 2496789 : c = fold_build2 (MINUS_EXPR, niter_type,
991 : fold_convert (niter_type, iv->base),
992 : fold_convert (niter_type, final));
993 2496789 : bounds_negate (bnds);
994 : }
995 : else
996 : {
997 4850045 : s = fold_convert (niter_type, iv->step);
998 4850045 : c = fold_build2 (MINUS_EXPR, niter_type,
999 : fold_convert (niter_type, final),
1000 : fold_convert (niter_type, iv->base));
1001 : }
1002 :
1003 7346834 : auto_mpz max;
1004 7346834 : number_of_iterations_ne_max (max, iv->no_overflow, c, s, bnds,
1005 : exit_must_be_taken);
1006 14693668 : niter->max = widest_int::from (wi::from_mpz (niter_type, max, false),
1007 14693668 : TYPE_SIGN (niter_type));
1008 :
1009 : /* Compute no-overflow information for the control iv. This can be
1010 : proven when below two conditions are satisfied:
1011 :
1012 : 1) IV evaluates toward FINAL at beginning, i.e:
1013 : base <= FINAL ; step > 0
1014 : base >= FINAL ; step < 0
1015 :
1016 : 2) |FINAL - base| is an exact multiple of step.
1017 :
1018 : Unfortunately, it's hard to prove above conditions after pass loop-ch
1019 : because loop with exit condition (IV != FINAL) usually will be guarded
1020 : by initial-condition (IV.base - IV.step != FINAL). In this case, we
1021 : can alternatively try to prove below conditions:
1022 :
1023 : 1') IV evaluates toward FINAL at beginning, i.e:
1024 : new_base = base - step < FINAL ; step > 0
1025 : && base - step doesn't underflow
1026 : new_base = base - step > FINAL ; step < 0
1027 : && base - step doesn't overflow
1028 :
1029 : Please refer to PR34114 as an example of loop-ch's impact.
1030 :
1031 : Note, for NE_EXPR, base equals to FINAL is a special case, in
1032 : which the loop exits immediately, and the iv does not overflow.
1033 :
1034 : Also note, we prove condition 2) by checking base and final separately
1035 : along with condition 1) or 1'). Since we ensure the difference
1036 : computation of c does not wrap with cond below and the adjusted s
1037 : will fit a signed type as well as an unsigned we can safely do
1038 : this using the type of the IV if it is not pointer typed. */
1039 7346834 : tree mtype = type;
1040 7346834 : if (POINTER_TYPE_P (type))
1041 576591 : mtype = niter_type;
1042 7346834 : if (!niter->control.no_overflow
1043 7346834 : && (integer_onep (s)
1044 198408 : || (multiple_of_p (mtype, fold_convert (mtype, iv->base),
1045 198408 : fold_convert (mtype, s), false)
1046 30170 : && multiple_of_p (mtype, fold_convert (mtype, final),
1047 30170 : fold_convert (mtype, s), false))))
1048 : {
1049 2336630 : tree t, cond, relaxed_cond = boolean_false_node;
1050 :
1051 2336630 : if (tree_int_cst_sign_bit (iv->step))
1052 : {
1053 2256550 : cond = fold_build2 (GE_EXPR, boolean_type_node, iv->base, final);
1054 2256550 : if (INTEGRAL_NB_TYPE_P (type))
1055 : {
1056 : /* Only when base - step doesn't overflow. */
1057 2256550 : t = TYPE_MAX_VALUE (type);
1058 2256550 : t = fold_build2 (PLUS_EXPR, type, t, iv->step);
1059 2256550 : t = fold_build2 (GE_EXPR, boolean_type_node, t, iv->base);
1060 2256550 : if (integer_nonzerop (t))
1061 : {
1062 2099676 : t = fold_build2 (MINUS_EXPR, type, iv->base, iv->step);
1063 2099676 : relaxed_cond = fold_build2 (GT_EXPR, boolean_type_node, t,
1064 : final);
1065 : }
1066 : }
1067 : }
1068 : else
1069 : {
1070 80080 : cond = fold_build2 (LE_EXPR, boolean_type_node, iv->base, final);
1071 80080 : if (INTEGRAL_NB_TYPE_P (type))
1072 : {
1073 : /* Only when base - step doesn't underflow. */
1074 80080 : t = TYPE_MIN_VALUE (type);
1075 80080 : t = fold_build2 (PLUS_EXPR, type, t, iv->step);
1076 80080 : t = fold_build2 (LE_EXPR, boolean_type_node, t, iv->base);
1077 80080 : if (integer_nonzerop (t))
1078 : {
1079 45268 : t = fold_build2 (MINUS_EXPR, type, iv->base, iv->step);
1080 45268 : relaxed_cond = fold_build2 (LT_EXPR, boolean_type_node, t,
1081 : final);
1082 : }
1083 : }
1084 : }
1085 :
1086 2336630 : t = simplify_using_initial_conditions (loop, cond);
1087 2336630 : if (!t || !integer_onep (t))
1088 57933 : t = simplify_using_initial_conditions (loop, relaxed_cond);
1089 :
1090 2336630 : if (t && integer_onep (t))
1091 : {
1092 2278976 : niter->control.no_overflow = true;
1093 2278976 : niter->niter = fold_build2 (EXACT_DIV_EXPR, niter_type, c, s);
1094 2278976 : return true;
1095 : }
1096 : }
1097 :
1098 : /* Let nsd (step, size of mode) = d. If d does not divide c, the loop
1099 : is infinite. Otherwise, the number of iterations is
1100 : (inverse(s/d) * (c/d)) mod (size of mode/d). */
1101 5067858 : bits = num_ending_zeros (s);
1102 15203574 : bound = build_low_bits_mask (niter_type,
1103 5067858 : (TYPE_PRECISION (niter_type)
1104 5067858 : - tree_to_uhwi (bits)));
1105 :
1106 5067858 : d = fold_binary_to_constant (LSHIFT_EXPR, niter_type,
1107 : build_int_cst (niter_type, 1), bits);
1108 5067858 : s = fold_binary_to_constant (RSHIFT_EXPR, niter_type, s, bits);
1109 :
1110 5067858 : if (!exit_must_be_taken)
1111 : {
1112 : /* If we cannot assume that the exit is taken eventually, record the
1113 : assumptions for divisibility of c. */
1114 1812139 : assumption = fold_build2 (FLOOR_MOD_EXPR, niter_type, c, d);
1115 1812139 : assumption = fold_build2 (EQ_EXPR, boolean_type_node,
1116 : assumption, build_int_cst (niter_type, 0));
1117 1812139 : if (!integer_nonzerop (assumption))
1118 285589 : niter->assumptions = fold_build2 (TRUTH_AND_EXPR, boolean_type_node,
1119 : niter->assumptions, assumption);
1120 : }
1121 :
1122 5067858 : c = fold_build2 (EXACT_DIV_EXPR, niter_type, c, d);
1123 5067858 : if (integer_onep (s))
1124 : {
1125 4894000 : niter->niter = c;
1126 : }
1127 : else
1128 : {
1129 173858 : tmp = fold_build2 (MULT_EXPR, niter_type, c, inverse (s, bound));
1130 173858 : niter->niter = fold_build2 (BIT_AND_EXPR, niter_type, tmp, bound);
1131 : }
1132 : return true;
1133 7346834 : }
1134 :
1135 : /* Checks whether we can determine the final value of the control variable
1136 : of the loop with ending condition IV0 < IV1 (computed in TYPE).
1137 : DELTA is the difference IV1->base - IV0->base, STEP is the absolute value
1138 : of the step. The assumptions necessary to ensure that the computation
1139 : of the final value does not overflow are recorded in NITER. If we
1140 : find the final value, we adjust DELTA and return TRUE. Otherwise
1141 : we return false. BNDS bounds the value of IV1->base - IV0->base,
1142 : and will be updated by the same amount as DELTA. EXIT_MUST_BE_TAKEN is
1143 : true if we know that the exit must be taken eventually. */
1144 :
1145 : static bool
1146 384053 : number_of_iterations_lt_to_ne (tree type, affine_iv *iv0, affine_iv *iv1,
1147 : class tree_niter_desc *niter,
1148 : tree *delta, tree step,
1149 : bool exit_must_be_taken, bounds *bnds)
1150 : {
1151 384053 : tree niter_type = TREE_TYPE (step);
1152 384053 : tree mod = fold_build2 (FLOOR_MOD_EXPR, niter_type, *delta, step);
1153 384053 : tree tmod;
1154 384053 : tree assumption = boolean_true_node, bound, noloop;
1155 384053 : bool fv_comp_no_overflow;
1156 384053 : tree type1 = type;
1157 384053 : if (POINTER_TYPE_P (type))
1158 124600 : type1 = sizetype;
1159 :
1160 384053 : if (TREE_CODE (mod) != INTEGER_CST)
1161 : return false;
1162 35004 : if (integer_nonzerop (mod))
1163 16271 : mod = fold_build2 (MINUS_EXPR, niter_type, step, mod);
1164 35004 : tmod = fold_convert (type1, mod);
1165 :
1166 35004 : auto_mpz mmod;
1167 35004 : wi::to_mpz (wi::to_wide (mod), mmod, UNSIGNED);
1168 35004 : mpz_neg (mmod, mmod);
1169 :
1170 : /* If the induction variable does not overflow and the exit is taken,
1171 : then the computation of the final value does not overflow. This is
1172 : also obviously the case if the new final value is equal to the
1173 : current one. Finally, we postulate this for pointer type variables,
1174 : as the code cannot rely on the object to that the pointer points being
1175 : placed at the end of the address space (and more pragmatically,
1176 : TYPE_{MIN,MAX}_VALUE is not defined for pointers). */
1177 35004 : if (integer_zerop (mod) || POINTER_TYPE_P (type))
1178 : fv_comp_no_overflow = true;
1179 15590 : else if (!exit_must_be_taken)
1180 : fv_comp_no_overflow = false;
1181 : else
1182 7921 : fv_comp_no_overflow =
1183 7921 : (iv0->no_overflow && integer_nonzerop (iv0->step))
1184 8849 : || (iv1->no_overflow && integer_nonzerop (iv1->step));
1185 :
1186 35004 : if (integer_nonzerop (iv0->step))
1187 : {
1188 : /* The final value of the iv is iv1->base + MOD, assuming that this
1189 : computation does not overflow, and that
1190 : iv0->base <= iv1->base + MOD. */
1191 30453 : if (!fv_comp_no_overflow)
1192 : {
1193 5884 : bound = fold_build2 (MINUS_EXPR, type1,
1194 : TYPE_MAX_VALUE (type1), tmod);
1195 5884 : assumption = fold_build2 (LE_EXPR, boolean_type_node,
1196 : iv1->base, bound);
1197 5884 : if (integer_zerop (assumption))
1198 : return false;
1199 : }
1200 : }
1201 : else
1202 : {
1203 : /* The final value of the iv is iv0->base - MOD, assuming that this
1204 : computation does not overflow, and that
1205 : iv0->base - MOD <= iv1->base. */
1206 4551 : if (!fv_comp_no_overflow)
1207 : {
1208 1785 : bound = fold_build2 (PLUS_EXPR, type1,
1209 : TYPE_MIN_VALUE (type1), tmod);
1210 1785 : assumption = fold_build2 (GE_EXPR, boolean_type_node,
1211 : iv0->base, bound);
1212 1785 : if (integer_zerop (assumption))
1213 : return false;
1214 : }
1215 : }
1216 :
1217 : /* IV0 < IV1 does not loop if IV0->base >= IV1->base. */
1218 34948 : if (fv_comp_no_overflow && mpz_cmp (mmod, bnds->below) < 0)
1219 16423 : noloop = boolean_false_node;
1220 : else
1221 18525 : noloop = fold_build2 (GE_EXPR, boolean_type_node,
1222 : iv0->base, iv1->base);
1223 :
1224 34948 : if (!integer_nonzerop (assumption))
1225 401 : niter->assumptions = fold_build2 (TRUTH_AND_EXPR, boolean_type_node,
1226 : niter->assumptions,
1227 : assumption);
1228 34948 : if (!integer_zerop (noloop))
1229 3660 : niter->may_be_zero = fold_build2 (TRUTH_OR_EXPR, boolean_type_node,
1230 : niter->may_be_zero,
1231 : noloop);
1232 34948 : bounds_add (bnds, wi::to_widest (mod), type);
1233 34948 : *delta = fold_build2 (PLUS_EXPR, niter_type, *delta, mod);
1234 :
1235 34948 : return true;
1236 35004 : }
1237 :
1238 : /* Add assertions to NITER that ensure that the control variable of the loop
1239 : with ending condition IV0 < IV1 does not overflow. Types of IV0 and IV1
1240 : are TYPE. Returns false if we can prove that there is an overflow, true
1241 : otherwise. STEP is the absolute value of the step. */
1242 :
1243 : static bool
1244 349105 : assert_no_overflow_lt (tree type, affine_iv *iv0, affine_iv *iv1,
1245 : class tree_niter_desc *niter, tree step)
1246 : {
1247 349105 : tree bound, d, assumption, diff;
1248 349105 : tree niter_type = TREE_TYPE (step);
1249 :
1250 349105 : if (integer_nonzerop (iv0->step))
1251 : {
1252 : /* for (i = iv0->base; i < iv1->base; i += iv0->step) */
1253 287023 : if (iv0->no_overflow)
1254 : return true;
1255 :
1256 : /* If iv0->base is a constant, we can determine the last value before
1257 : overflow precisely; otherwise we conservatively assume
1258 : MAX - STEP + 1. */
1259 :
1260 47181 : if (TREE_CODE (iv0->base) == INTEGER_CST)
1261 : {
1262 16087 : d = fold_build2 (MINUS_EXPR, niter_type,
1263 : fold_convert (niter_type, TYPE_MAX_VALUE (type)),
1264 : fold_convert (niter_type, iv0->base));
1265 16087 : diff = fold_build2 (FLOOR_MOD_EXPR, niter_type, d, step);
1266 : }
1267 : else
1268 31094 : diff = fold_build2 (MINUS_EXPR, niter_type, step,
1269 : build_int_cst (niter_type, 1));
1270 47181 : bound = fold_build2 (MINUS_EXPR, type,
1271 : TYPE_MAX_VALUE (type), fold_convert (type, diff));
1272 47181 : assumption = fold_build2 (LE_EXPR, boolean_type_node,
1273 : iv1->base, bound);
1274 : }
1275 : else
1276 : {
1277 : /* for (i = iv1->base; i > iv0->base; i += iv1->step) */
1278 62082 : if (iv1->no_overflow)
1279 : return true;
1280 :
1281 31577 : if (TREE_CODE (iv1->base) == INTEGER_CST)
1282 : {
1283 56 : d = fold_build2 (MINUS_EXPR, niter_type,
1284 : fold_convert (niter_type, iv1->base),
1285 : fold_convert (niter_type, TYPE_MIN_VALUE (type)));
1286 56 : diff = fold_build2 (FLOOR_MOD_EXPR, niter_type, d, step);
1287 : }
1288 : else
1289 31521 : diff = fold_build2 (MINUS_EXPR, niter_type, step,
1290 : build_int_cst (niter_type, 1));
1291 31577 : bound = fold_build2 (PLUS_EXPR, type,
1292 : TYPE_MIN_VALUE (type), fold_convert (type, diff));
1293 31577 : assumption = fold_build2 (GE_EXPR, boolean_type_node,
1294 : iv0->base, bound);
1295 : }
1296 :
1297 78758 : if (integer_zerop (assumption))
1298 : return false;
1299 78694 : if (!integer_nonzerop (assumption))
1300 56457 : niter->assumptions = fold_build2 (TRUTH_AND_EXPR, boolean_type_node,
1301 : niter->assumptions, assumption);
1302 :
1303 78694 : iv0->no_overflow = true;
1304 78694 : iv1->no_overflow = true;
1305 78694 : return true;
1306 : }
1307 :
1308 : /* Add an assumption to NITER that a loop whose ending condition
1309 : is IV0 < IV1 rolls. TYPE is the type of the control iv. BNDS
1310 : bounds the value of IV1->base - IV0->base. */
1311 :
1312 : static void
1313 349041 : assert_loop_rolls_lt (tree type, affine_iv *iv0, affine_iv *iv1,
1314 : class tree_niter_desc *niter, bounds *bnds)
1315 : {
1316 349041 : tree assumption = boolean_true_node, bound, diff;
1317 349041 : tree mbz, mbzl, mbzr, type1;
1318 349041 : bool rolls_p, no_overflow_p;
1319 349041 : widest_int dstep;
1320 349041 : mpz_t mstep, max;
1321 :
1322 : /* We are going to compute the number of iterations as
1323 : (iv1->base - iv0->base + step - 1) / step, computed in the unsigned
1324 : variant of TYPE. This formula only works if
1325 :
1326 : -step + 1 <= (iv1->base - iv0->base) <= MAX - step + 1
1327 :
1328 : (where MAX is the maximum value of the unsigned variant of TYPE, and
1329 : the computations in this formula are performed in full precision,
1330 : i.e., without overflows).
1331 :
1332 : Usually, for loops with exit condition iv0->base + step * i < iv1->base,
1333 : we have a condition of the form iv0->base - step < iv1->base before the loop,
1334 : and for loops iv0->base < iv1->base - step * i the condition
1335 : iv0->base < iv1->base + step, due to loop header copying, which enable us
1336 : to prove the lower bound.
1337 :
1338 : The upper bound is more complicated. Unless the expressions for initial
1339 : and final value themselves contain enough information, we usually cannot
1340 : derive it from the context. */
1341 :
1342 : /* First check whether the answer does not follow from the bounds we gathered
1343 : before. */
1344 349041 : if (integer_nonzerop (iv0->step))
1345 287023 : dstep = wi::to_widest (iv0->step);
1346 : else
1347 : {
1348 62018 : dstep = wi::sext (wi::to_widest (iv1->step), TYPE_PRECISION (type));
1349 62018 : dstep = -dstep;
1350 : }
1351 :
1352 349041 : mpz_init (mstep);
1353 349041 : wi::to_mpz (dstep, mstep, UNSIGNED);
1354 349041 : mpz_neg (mstep, mstep);
1355 349041 : mpz_add_ui (mstep, mstep, 1);
1356 :
1357 349041 : rolls_p = mpz_cmp (mstep, bnds->below) <= 0;
1358 :
1359 349041 : mpz_init (max);
1360 349041 : wi::to_mpz (wi::minus_one (TYPE_PRECISION (type)), max, UNSIGNED);
1361 349041 : mpz_add (max, max, mstep);
1362 698082 : no_overflow_p = (mpz_cmp (bnds->up, max) <= 0
1363 : /* For pointers, only values lying inside a single object
1364 : can be compared or manipulated by pointer arithmetics.
1365 : Gcc in general does not allow or handle objects larger
1366 : than half of the address space, hence the upper bound
1367 : is satisfied for pointers. */
1368 349041 : || POINTER_TYPE_P (type));
1369 349041 : mpz_clear (mstep);
1370 349041 : mpz_clear (max);
1371 :
1372 349041 : if (rolls_p && no_overflow_p)
1373 131197 : return;
1374 :
1375 217844 : type1 = type;
1376 217844 : if (POINTER_TYPE_P (type))
1377 63851 : type1 = sizetype;
1378 :
1379 : /* Now the hard part; we must formulate the assumption(s) as expressions, and
1380 : we must be careful not to introduce overflow. */
1381 :
1382 217844 : if (integer_nonzerop (iv0->step))
1383 : {
1384 177047 : diff = fold_build2 (MINUS_EXPR, type1,
1385 : iv0->step, build_int_cst (type1, 1));
1386 :
1387 : /* We need to know that iv0->base >= MIN + iv0->step - 1. Since
1388 : 0 address never belongs to any object, we can assume this for
1389 : pointers. */
1390 177047 : if (!POINTER_TYPE_P (type))
1391 : {
1392 117034 : bound = fold_build2 (PLUS_EXPR, type1,
1393 : TYPE_MIN_VALUE (type), diff);
1394 117034 : assumption = fold_build2 (GE_EXPR, boolean_type_node,
1395 : iv0->base, bound);
1396 : }
1397 :
1398 : /* And then we can compute iv0->base - diff, and compare it with
1399 : iv1->base. */
1400 177047 : mbzl = fold_build2 (MINUS_EXPR, type1,
1401 : fold_convert (type1, iv0->base), diff);
1402 177047 : mbzr = fold_convert (type1, iv1->base);
1403 : }
1404 : else
1405 : {
1406 40797 : diff = fold_build2 (PLUS_EXPR, type1,
1407 : iv1->step, build_int_cst (type1, 1));
1408 :
1409 40797 : if (!POINTER_TYPE_P (type))
1410 : {
1411 36959 : bound = fold_build2 (PLUS_EXPR, type1,
1412 : TYPE_MAX_VALUE (type), diff);
1413 36959 : assumption = fold_build2 (LE_EXPR, boolean_type_node,
1414 : iv1->base, bound);
1415 : }
1416 :
1417 40797 : mbzl = fold_convert (type1, iv0->base);
1418 40797 : mbzr = fold_build2 (MINUS_EXPR, type1,
1419 : fold_convert (type1, iv1->base), diff);
1420 : }
1421 :
1422 217844 : if (!integer_nonzerop (assumption))
1423 93217 : niter->assumptions = fold_build2 (TRUTH_AND_EXPR, boolean_type_node,
1424 : niter->assumptions, assumption);
1425 217844 : if (!rolls_p)
1426 : {
1427 201325 : mbz = fold_build2 (GT_EXPR, boolean_type_node, mbzl, mbzr);
1428 201325 : niter->may_be_zero = fold_build2 (TRUTH_OR_EXPR, boolean_type_node,
1429 : niter->may_be_zero, mbz);
1430 : }
1431 349041 : }
1432 :
1433 : /* Determines number of iterations of loop whose ending condition
1434 : is IV0 < IV1 which likes: {base, -C} < n, or n < {base, C}.
1435 : The number of iterations is stored to NITER. */
1436 :
1437 : static bool
1438 67253 : number_of_iterations_until_wrap (class loop *loop, tree type, affine_iv *iv0,
1439 : affine_iv *iv1, class tree_niter_desc *niter)
1440 : {
1441 67253 : tree niter_type = unsigned_type_for (type);
1442 67253 : tree step, num, assumptions, may_be_zero, span;
1443 67253 : wide_int high, low, max, min;
1444 :
1445 67253 : may_be_zero = fold_build2 (LE_EXPR, boolean_type_node, iv1->base, iv0->base);
1446 67253 : if (integer_onep (may_be_zero))
1447 : return false;
1448 :
1449 67043 : int prec = TYPE_PRECISION (type);
1450 67043 : signop sgn = TYPE_SIGN (type);
1451 67043 : min = wi::min_value (prec, sgn);
1452 67043 : max = wi::max_value (prec, sgn);
1453 :
1454 : /* n < {base, C}. */
1455 67043 : if (integer_zerop (iv0->step) && !tree_int_cst_sign_bit (iv1->step))
1456 : {
1457 : /* MIN + C - 1 <= n. */
1458 42330 : tree last = wide_int_to_tree (type, min + wi::to_wide (iv1->step) - 1);
1459 42330 : assumptions = fold_build2 (LE_EXPR, boolean_type_node, last, iv0->base);
1460 42330 : if (integer_zerop (assumptions))
1461 : return false;
1462 :
1463 42330 : step = fold_convert (niter_type, iv1->step);
1464 42330 : num = fold_build2 (MINUS_EXPR, niter_type,
1465 : wide_int_to_tree (niter_type, max),
1466 : fold_convert (niter_type, iv1->base));
1467 :
1468 : /* When base has the form iv + 1, if we know iv >= n, then iv + 1 < n
1469 : only when iv + 1 overflows, i.e. when iv == TYPE_VALUE_MAX. */
1470 42330 : if (sgn == UNSIGNED
1471 5909 : && integer_onep (step)
1472 914 : && TREE_CODE (iv1->base) == PLUS_EXPR
1473 42915 : && integer_onep (TREE_OPERAND (iv1->base, 1)))
1474 : {
1475 434 : tree cond = fold_build2 (GE_EXPR, boolean_type_node,
1476 : TREE_OPERAND (iv1->base, 0), iv0->base);
1477 434 : cond = simplify_using_initial_conditions (loop, cond);
1478 434 : if (integer_onep (cond))
1479 16 : may_be_zero = fold_build2 (EQ_EXPR, boolean_type_node,
1480 : TREE_OPERAND (iv1->base, 0),
1481 : TYPE_MAX_VALUE (type));
1482 : }
1483 :
1484 42330 : high = max;
1485 42330 : if (TREE_CODE (iv1->base) == INTEGER_CST)
1486 29890 : low = wi::to_wide (iv1->base) - 1;
1487 12440 : else if (TREE_CODE (iv0->base) == INTEGER_CST)
1488 5726 : low = wi::to_wide (iv0->base);
1489 : else
1490 6714 : low = min;
1491 : }
1492 : /* {base, -C} < n. */
1493 24713 : else if (tree_int_cst_sign_bit (iv0->step) && integer_zerop (iv1->step))
1494 : {
1495 : /* MAX + (-C) + 1 >= n. */
1496 24713 : tree last = wide_int_to_tree (type, max + wi::to_wide (iv0->step) + 1);
1497 24713 : assumptions = fold_build2 (GE_EXPR, boolean_type_node, last, iv1->base);
1498 24713 : if (integer_zerop (assumptions))
1499 : return false;
1500 :
1501 24711 : step = fold_build1 (NEGATE_EXPR, niter_type,
1502 : fold_convert (niter_type, iv0->step));
1503 24711 : num = fold_build2 (MINUS_EXPR, niter_type,
1504 : fold_convert (niter_type, iv0->base),
1505 : wide_int_to_tree (niter_type, min));
1506 24711 : low = min;
1507 24711 : if (TREE_CODE (iv0->base) == INTEGER_CST)
1508 1321 : high = wi::to_wide (iv0->base) + 1;
1509 23390 : else if (TREE_CODE (iv1->base) == INTEGER_CST)
1510 2294 : high = wi::to_wide (iv1->base);
1511 : else
1512 21096 : high = max;
1513 : }
1514 : else
1515 0 : return false;
1516 :
1517 : /* (delta + step - 1) / step */
1518 67041 : num = fold_build2 (PLUS_EXPR, niter_type, num, step);
1519 67041 : niter->niter = fold_build2 (FLOOR_DIV_EXPR, niter_type, num, step);
1520 :
1521 67041 : widest_int delta, s;
1522 67041 : delta = widest_int::from (high, sgn) - widest_int::from (low, sgn);
1523 67041 : s = wi::to_widest (step);
1524 67041 : delta = delta + s - 1;
1525 67041 : niter->max = wi::udiv_floor (delta, s);
1526 :
1527 67041 : niter->may_be_zero = may_be_zero;
1528 :
1529 67041 : if (!integer_nonzerop (assumptions))
1530 9245 : niter->assumptions = fold_build2 (TRUTH_AND_EXPR, boolean_type_node,
1531 : niter->assumptions, assumptions);
1532 :
1533 67041 : niter->control.no_overflow = false;
1534 :
1535 : /* Update bound and exit condition as:
1536 : bound = niter * STEP + (IVbase - STEP).
1537 : { IVbase - STEP, +, STEP } != bound
1538 : Here, biasing IVbase by 1 step makes 'bound' be the value before wrap.
1539 : */
1540 67041 : tree base_type = TREE_TYPE (niter->control.base);
1541 67041 : if (POINTER_TYPE_P (base_type))
1542 : {
1543 6527 : tree utype = unsigned_type_for (base_type);
1544 6527 : niter->control.base
1545 6527 : = fold_build2 (MINUS_EXPR, utype,
1546 : fold_convert (utype, niter->control.base),
1547 : fold_convert (utype, niter->control.step));
1548 6527 : niter->control.base = fold_convert (base_type, niter->control.base);
1549 : }
1550 : else
1551 60514 : niter->control.base
1552 60514 : = fold_build2 (MINUS_EXPR, base_type, niter->control.base,
1553 : niter->control.step);
1554 :
1555 67041 : span = fold_build2 (MULT_EXPR, niter_type, niter->niter,
1556 : fold_convert (niter_type, niter->control.step));
1557 67041 : niter->bound = fold_build2 (PLUS_EXPR, niter_type, span,
1558 : fold_convert (niter_type, niter->control.base));
1559 67041 : niter->bound = fold_convert (type, niter->bound);
1560 67041 : niter->cmp = NE_EXPR;
1561 :
1562 67041 : return true;
1563 134294 : }
1564 :
1565 : /* Determines number of iterations of loop whose ending condition
1566 : is IV0 < IV1. TYPE is the type of the iv. The number of
1567 : iterations is stored to NITER. BNDS bounds the difference
1568 : IV1->base - IV0->base. EXIT_MUST_BE_TAKEN is true if we know
1569 : that the exit must be taken eventually. */
1570 :
1571 : static bool
1572 5338377 : number_of_iterations_lt (class loop *loop, tree type, affine_iv *iv0,
1573 : affine_iv *iv1, class tree_niter_desc *niter,
1574 : bool exit_must_be_taken, bounds *bnds)
1575 : {
1576 5338377 : tree niter_type = unsigned_type_for (type);
1577 5338377 : tree delta, step, s;
1578 5338377 : mpz_t mstep, tmp;
1579 :
1580 5338377 : if (integer_nonzerop (iv0->step))
1581 : {
1582 5010385 : niter->control = *iv0;
1583 5010385 : niter->cmp = LT_EXPR;
1584 5010385 : niter->bound = iv1->base;
1585 : }
1586 : else
1587 : {
1588 327992 : niter->control = *iv1;
1589 327992 : niter->cmp = GT_EXPR;
1590 327992 : niter->bound = iv0->base;
1591 : }
1592 :
1593 : /* {base, -C} < n, or n < {base, C} */
1594 5338377 : if (tree_int_cst_sign_bit (iv0->step)
1595 5338377 : || (!integer_zerop (iv1->step) && !tree_int_cst_sign_bit (iv1->step)))
1596 67253 : return number_of_iterations_until_wrap (loop, type, iv0, iv1, niter);
1597 :
1598 5271124 : delta = fold_build2 (MINUS_EXPR, niter_type,
1599 : fold_convert (niter_type, iv1->base),
1600 : fold_convert (niter_type, iv0->base));
1601 :
1602 : /* First handle the special case that the step is +-1. */
1603 9939320 : if ((integer_onep (iv0->step) && integer_zerop (iv1->step))
1604 5271124 : || (integer_all_onesp (iv1->step) && integer_zerop (iv0->step)))
1605 : {
1606 : /* for (i = iv0->base; i < iv1->base; i++)
1607 :
1608 : or
1609 :
1610 : for (i = iv1->base; i > iv0->base; i--).
1611 :
1612 : In both cases # of iterations is iv1->base - iv0->base, assuming that
1613 : iv1->base >= iv0->base.
1614 :
1615 : First try to derive a lower bound on the value of
1616 : iv1->base - iv0->base, computed in full precision. If the difference
1617 : is nonnegative, we are done, otherwise we must record the
1618 : condition. */
1619 :
1620 4887071 : if (mpz_sgn (bnds->below) < 0)
1621 1830531 : niter->may_be_zero = fold_build2 (LT_EXPR, boolean_type_node,
1622 : iv1->base, iv0->base);
1623 4887071 : niter->niter = delta;
1624 9774142 : niter->max = widest_int::from (wi::from_mpz (niter_type, bnds->up, false),
1625 9774142 : TYPE_SIGN (niter_type));
1626 4887071 : niter->control.no_overflow = true;
1627 4887071 : return true;
1628 : }
1629 :
1630 384053 : if (integer_nonzerop (iv0->step))
1631 317476 : step = fold_convert (niter_type, iv0->step);
1632 : else
1633 66577 : step = fold_build1 (NEGATE_EXPR, niter_type,
1634 : fold_convert (niter_type, iv1->step));
1635 :
1636 : /* If we can determine the final value of the control iv exactly, we can
1637 : transform the condition to != comparison. In particular, this will be
1638 : the case if DELTA is constant. */
1639 384053 : if (number_of_iterations_lt_to_ne (type, iv0, iv1, niter, &delta, step,
1640 : exit_must_be_taken, bnds))
1641 : {
1642 34948 : affine_iv zps;
1643 :
1644 34948 : zps.base = build_int_cst (niter_type, 0);
1645 34948 : zps.step = step;
1646 : /* number_of_iterations_lt_to_ne will add assumptions that ensure that
1647 : zps does not overflow. */
1648 34948 : zps.no_overflow = true;
1649 :
1650 34948 : return number_of_iterations_ne (loop, type, &zps,
1651 : delta, niter, true, bnds);
1652 : }
1653 :
1654 : /* Make sure that the control iv does not overflow. */
1655 349105 : if (!assert_no_overflow_lt (type, iv0, iv1, niter, step))
1656 : return false;
1657 :
1658 : /* We determine the number of iterations as (delta + step - 1) / step. For
1659 : this to work, we must know that iv1->base >= iv0->base - step + 1,
1660 : otherwise the loop does not roll. */
1661 349041 : assert_loop_rolls_lt (type, iv0, iv1, niter, bnds);
1662 :
1663 349041 : s = fold_build2 (MINUS_EXPR, niter_type,
1664 : step, build_int_cst (niter_type, 1));
1665 349041 : delta = fold_build2 (PLUS_EXPR, niter_type, delta, s);
1666 349041 : niter->niter = fold_build2 (FLOOR_DIV_EXPR, niter_type, delta, step);
1667 :
1668 349041 : mpz_init (mstep);
1669 349041 : mpz_init (tmp);
1670 349041 : wi::to_mpz (wi::to_wide (step), mstep, UNSIGNED);
1671 349041 : mpz_add (tmp, bnds->up, mstep);
1672 349041 : mpz_sub_ui (tmp, tmp, 1);
1673 349041 : mpz_fdiv_q (tmp, tmp, mstep);
1674 698082 : niter->max = widest_int::from (wi::from_mpz (niter_type, tmp, false),
1675 698082 : TYPE_SIGN (niter_type));
1676 349041 : mpz_clear (mstep);
1677 349041 : mpz_clear (tmp);
1678 :
1679 349041 : return true;
1680 : }
1681 :
1682 : /* Determines number of iterations of loop whose ending condition
1683 : is IV0 <= IV1. TYPE is the type of the iv. The number of
1684 : iterations is stored to NITER. EXIT_MUST_BE_TAKEN is true if
1685 : we know that this condition must eventually become false (we derived this
1686 : earlier, and possibly set NITER->assumptions to make sure this
1687 : is the case). BNDS bounds the difference IV1->base - IV0->base. */
1688 :
1689 : static bool
1690 2003457 : number_of_iterations_le (class loop *loop, tree type, affine_iv *iv0,
1691 : affine_iv *iv1, class tree_niter_desc *niter,
1692 : bool exit_must_be_taken, bounds *bnds)
1693 : {
1694 2003457 : tree assumption;
1695 2003457 : tree type1 = type;
1696 2003457 : if (POINTER_TYPE_P (type))
1697 6250 : type1 = sizetype;
1698 :
1699 : /* Say that IV0 is the control variable. Then IV0 <= IV1 iff
1700 : IV0 < IV1 + 1, assuming that IV1 is not equal to the greatest
1701 : value of the type. This we must know anyway, since if it is
1702 : equal to this value, the loop rolls forever. We do not check
1703 : this condition for pointer type ivs, as the code cannot rely on
1704 : the object to that the pointer points being placed at the end of
1705 : the address space (and more pragmatically, TYPE_{MIN,MAX}_VALUE is
1706 : not defined for pointers). */
1707 :
1708 2003457 : if (!exit_must_be_taken && !POINTER_TYPE_P (type))
1709 : {
1710 625953 : if (integer_nonzerop (iv0->step))
1711 561634 : assumption = fold_build2 (NE_EXPR, boolean_type_node,
1712 : iv1->base, TYPE_MAX_VALUE (type));
1713 : else
1714 64319 : assumption = fold_build2 (NE_EXPR, boolean_type_node,
1715 : iv0->base, TYPE_MIN_VALUE (type));
1716 :
1717 625953 : if (integer_zerop (assumption))
1718 : return false;
1719 625953 : if (!integer_nonzerop (assumption))
1720 247224 : niter->assumptions = fold_build2 (TRUTH_AND_EXPR, boolean_type_node,
1721 : niter->assumptions, assumption);
1722 : }
1723 :
1724 2003457 : if (integer_nonzerop (iv0->step))
1725 : {
1726 1906564 : if (POINTER_TYPE_P (type))
1727 1215 : iv1->base = fold_build_pointer_plus_hwi (iv1->base, 1);
1728 : else
1729 1905349 : iv1->base = fold_build2 (PLUS_EXPR, type1, iv1->base,
1730 : build_int_cst (type1, 1));
1731 : }
1732 96893 : else if (POINTER_TYPE_P (type))
1733 5035 : iv0->base = fold_build_pointer_plus_hwi (iv0->base, -1);
1734 : else
1735 91858 : iv0->base = fold_build2 (MINUS_EXPR, type1,
1736 : iv0->base, build_int_cst (type1, 1));
1737 :
1738 2003457 : bounds_add (bnds, 1, type1);
1739 :
1740 2003457 : return number_of_iterations_lt (loop, type, iv0, iv1, niter, exit_must_be_taken,
1741 2003457 : bnds);
1742 : }
1743 :
1744 : /* Dumps description of affine induction variable IV to FILE. */
1745 :
1746 : static void
1747 86236 : dump_affine_iv (FILE *file, affine_iv *iv)
1748 : {
1749 86236 : if (!integer_zerop (iv->step))
1750 43118 : fprintf (file, "[");
1751 :
1752 86236 : print_generic_expr (file, iv->base, TDF_SLIM);
1753 :
1754 86236 : if (!integer_zerop (iv->step))
1755 : {
1756 43118 : fprintf (file, ", + , ");
1757 43118 : print_generic_expr (file, iv->step, TDF_SLIM);
1758 77201 : fprintf (file, "]%s", iv->no_overflow ? "(no_overflow)" : "");
1759 : }
1760 86236 : }
1761 :
1762 : DEBUG_FUNCTION void
1763 0 : debug (affine_iv *iv)
1764 : {
1765 0 : dump_affine_iv (stderr, iv);
1766 0 : fputc ('\n', stderr);
1767 0 : }
1768 :
1769 : /* Determine the number of iterations according to condition (for staying
1770 : inside loop) which compares two induction variables using comparison
1771 : operator CODE. The induction variable on left side of the comparison
1772 : is IV0, the right-hand side is IV1. Both induction variables must have
1773 : type TYPE, which must be an integer or pointer type. The steps of the
1774 : ivs must be constants (or NULL_TREE, which is interpreted as constant zero).
1775 :
1776 : LOOP is the loop whose number of iterations we are determining.
1777 :
1778 : ONLY_EXIT is true if we are sure this is the only way the loop could be
1779 : exited (including possibly non-returning function calls, exceptions, etc.)
1780 : -- in this case we can use the information whether the control induction
1781 : variables can overflow or not in a more efficient way.
1782 :
1783 : if EVERY_ITERATION is true, we know the test is executed on every iteration.
1784 :
1785 : The results (number of iterations and assumptions as described in
1786 : comments at class tree_niter_desc in tree-ssa-loop.h) are stored to NITER.
1787 : Returns false if it fails to determine number of iterations, true if it
1788 : was determined (possibly with some assumptions). */
1789 :
1790 : static bool
1791 12872681 : number_of_iterations_cond (class loop *loop,
1792 : tree type, affine_iv *iv0, enum tree_code code,
1793 : affine_iv *iv1, class tree_niter_desc *niter,
1794 : bool only_exit, bool every_iteration)
1795 : {
1796 12872681 : bool exit_must_be_taken = false, ret;
1797 12872681 : bounds bnds;
1798 :
1799 : /* If the test is not executed every iteration, wrapping may make the test
1800 : to pass again.
1801 : TODO: the overflow case can be still used as unreliable estimate of upper
1802 : bound. But we have no API to pass it down to number of iterations code
1803 : and, at present, it will not use it anyway. */
1804 12872681 : if (!every_iteration
1805 70285 : && (!iv0->no_overflow || !iv1->no_overflow
1806 48865 : || code == NE_EXPR || code == EQ_EXPR))
1807 : return false;
1808 :
1809 : /* The meaning of these assumptions is this:
1810 : if !assumptions
1811 : then the rest of information does not have to be valid
1812 : if may_be_zero then the loop does not roll, even if
1813 : niter != 0. */
1814 12823963 : niter->assumptions = boolean_true_node;
1815 12823963 : niter->may_be_zero = boolean_false_node;
1816 12823963 : niter->niter = NULL_TREE;
1817 12823963 : niter->max = 0;
1818 12823963 : niter->bound = NULL_TREE;
1819 12823963 : niter->cmp = ERROR_MARK;
1820 :
1821 : /* Make < comparison from > ones, and for NE_EXPR comparisons, ensure that
1822 : the control variable is on lhs. */
1823 12823963 : if (code == GE_EXPR || code == GT_EXPR
1824 12823963 : || (code == NE_EXPR && integer_zerop (iv0->step)))
1825 : {
1826 2974434 : std::swap (iv0, iv1);
1827 2974434 : code = swap_tree_comparison (code);
1828 : }
1829 :
1830 12823963 : if (POINTER_TYPE_P (type))
1831 : {
1832 : /* Comparison of pointers is undefined unless both iv0 and iv1 point
1833 : to the same object. If they do, the control variable cannot wrap
1834 : (as wrap around the bounds of memory will never return a pointer
1835 : that would be guaranteed to point to the same object, even if we
1836 : avoid undefined behavior by casting to size_t and back). */
1837 757224 : iv0->no_overflow = true;
1838 757224 : iv1->no_overflow = true;
1839 : }
1840 :
1841 : /* If the control induction variable does not overflow and the only exit
1842 : from the loop is the one that we analyze, we know it must be taken
1843 : eventually. */
1844 12823963 : if (only_exit)
1845 : {
1846 8395988 : if (!integer_zerop (iv0->step) && iv0->no_overflow)
1847 : exit_must_be_taken = true;
1848 2105284 : else if (!integer_zerop (iv1->step) && iv1->no_overflow)
1849 6445713 : exit_must_be_taken = true;
1850 : }
1851 :
1852 : /* We can handle cases which neither of the sides of the comparison is
1853 : invariant:
1854 :
1855 : {iv0.base, iv0.step} cmp_code {iv1.base, iv1.step}
1856 : as if:
1857 : {iv0.base, iv0.step - iv1.step} cmp_code {iv1.base, 0}
1858 :
1859 : provided that either below condition is satisfied:
1860 :
1861 : a) the test is NE_EXPR;
1862 : b) iv0 and iv1 do not overflow and iv0.step - iv1.step is of
1863 : the same sign and of less or equal magnitude than iv0.step
1864 :
1865 : This rarely occurs in practice, but it is simple enough to manage. */
1866 12823963 : if (!integer_zerop (iv0->step) && !integer_zerop (iv1->step))
1867 : {
1868 5255 : tree step_type = POINTER_TYPE_P (type) ? sizetype : type;
1869 5255 : tree step = fold_binary_to_constant (MINUS_EXPR, step_type,
1870 : iv0->step, iv1->step);
1871 :
1872 : /* For code other than NE_EXPR we have to ensure moving the evolution
1873 : of IV1 to that of IV0 does not introduce overflow. */
1874 5255 : if (TREE_CODE (step) != INTEGER_CST
1875 5255 : || !iv0->no_overflow || !iv1->no_overflow)
1876 : {
1877 1000 : if (code != NE_EXPR)
1878 : return false;
1879 0 : iv0->no_overflow = false;
1880 : }
1881 : /* If the new step of IV0 has changed sign or is of greater
1882 : magnitude then we do not know whether IV0 does overflow
1883 : and thus the transform is not valid for code other than NE_EXPR. */
1884 4255 : else if (tree_int_cst_sign_bit (step) != tree_int_cst_sign_bit (iv0->step)
1885 7831 : || wi::gtu_p (wi::abs (wi::to_widest (step)),
1886 11407 : wi::abs (wi::to_widest (iv0->step))))
1887 : {
1888 2931 : if (POINTER_TYPE_P (type) && code != NE_EXPR)
1889 : /* For relational pointer compares we have further guarantees
1890 : that the pointers always point to the same object (or one
1891 : after it) and that objects do not cross the zero page. So
1892 : not only is the transform always valid for relational
1893 : pointer compares, we also know the resulting IV does not
1894 : overflow. */
1895 : ;
1896 786 : else if (code != NE_EXPR)
1897 : return false;
1898 : else
1899 499 : iv0->no_overflow = false;
1900 : }
1901 :
1902 3469 : iv0->step = step;
1903 3469 : iv1->step = build_int_cst (step_type, 0);
1904 3469 : iv1->no_overflow = true;
1905 : }
1906 :
1907 : /* If the result of the comparison is a constant, the loop is weird. More
1908 : precise handling would be possible, but the situation is not common enough
1909 : to waste time on it. */
1910 12822177 : if (integer_zerop (iv0->step) && integer_zerop (iv1->step))
1911 : return false;
1912 :
1913 : /* If the loop exits immediately, there is nothing to do. */
1914 12734239 : tree tem = fold_binary (code, boolean_type_node, iv0->base, iv1->base);
1915 12734239 : if (tem && integer_zerop (tem))
1916 : {
1917 83976 : if (!every_iteration)
1918 : return false;
1919 83913 : niter->niter = build_int_cst (unsigned_type_for (type), 0);
1920 83913 : niter->max = 0;
1921 83913 : return true;
1922 : }
1923 :
1924 : /* OK, now we know we have a senseful loop. Handle several cases, depending
1925 : on what comparison operator is used. */
1926 12650263 : bound_difference (loop, iv1->base, iv0->base, &bnds);
1927 :
1928 12650263 : if (dump_file && (dump_flags & TDF_DETAILS))
1929 : {
1930 43118 : fprintf (dump_file,
1931 : "Analyzing # of iterations of loop %d\n", loop->num);
1932 :
1933 43118 : fprintf (dump_file, " exit condition ");
1934 43118 : dump_affine_iv (dump_file, iv0);
1935 51406 : fprintf (dump_file, " %s ",
1936 : code == NE_EXPR ? "!="
1937 8288 : : code == LT_EXPR ? "<"
1938 : : "<=");
1939 43118 : dump_affine_iv (dump_file, iv1);
1940 43118 : fprintf (dump_file, "\n");
1941 :
1942 43118 : fprintf (dump_file, " bounds on difference of bases: ");
1943 43118 : mpz_out_str (dump_file, 10, bnds.below);
1944 43118 : fprintf (dump_file, " ... ");
1945 43118 : mpz_out_str (dump_file, 10, bnds.up);
1946 43118 : fprintf (dump_file, "\n");
1947 : }
1948 :
1949 12650263 : switch (code)
1950 : {
1951 7311886 : case NE_EXPR:
1952 7311886 : gcc_assert (integer_zerop (iv1->step));
1953 7311886 : ret = number_of_iterations_ne (loop, type, iv0, iv1->base, niter,
1954 : exit_must_be_taken, &bnds);
1955 7311886 : break;
1956 :
1957 3334920 : case LT_EXPR:
1958 3334920 : ret = number_of_iterations_lt (loop, type, iv0, iv1, niter,
1959 : exit_must_be_taken, &bnds);
1960 3334920 : break;
1961 :
1962 2003457 : case LE_EXPR:
1963 2003457 : ret = number_of_iterations_le (loop, type, iv0, iv1, niter,
1964 : exit_must_be_taken, &bnds);
1965 2003457 : break;
1966 :
1967 0 : default:
1968 0 : gcc_unreachable ();
1969 : }
1970 :
1971 12650263 : mpz_clear (bnds.up);
1972 12650263 : mpz_clear (bnds.below);
1973 :
1974 12650263 : if (dump_file && (dump_flags & TDF_DETAILS))
1975 : {
1976 43118 : if (ret)
1977 : {
1978 43118 : fprintf (dump_file, " result:\n");
1979 43118 : if (!integer_nonzerop (niter->assumptions))
1980 : {
1981 222 : fprintf (dump_file, " under assumptions ");
1982 222 : print_generic_expr (dump_file, niter->assumptions, TDF_SLIM);
1983 222 : fprintf (dump_file, "\n");
1984 : }
1985 :
1986 43118 : if (!integer_zerop (niter->may_be_zero))
1987 : {
1988 799 : fprintf (dump_file, " zero if ");
1989 799 : print_generic_expr (dump_file, niter->may_be_zero, TDF_SLIM);
1990 799 : fprintf (dump_file, "\n");
1991 : }
1992 :
1993 43118 : fprintf (dump_file, " # of iterations ");
1994 43118 : print_generic_expr (dump_file, niter->niter, TDF_SLIM);
1995 43118 : fprintf (dump_file, ", bounded by ");
1996 43118 : print_decu (niter->max, dump_file);
1997 43118 : fprintf (dump_file, "\n");
1998 : }
1999 : else
2000 0 : fprintf (dump_file, " failed\n\n");
2001 : }
2002 : return ret;
2003 : }
2004 :
2005 : /* Return an expression that computes the popcount of src. */
2006 :
2007 : static tree
2008 2087 : build_popcount_expr (tree src)
2009 : {
2010 2087 : tree fn;
2011 2087 : bool use_ifn = false;
2012 2087 : int prec = TYPE_PRECISION (TREE_TYPE (src));
2013 2087 : int i_prec = TYPE_PRECISION (integer_type_node);
2014 2087 : int li_prec = TYPE_PRECISION (long_integer_type_node);
2015 2087 : int lli_prec = TYPE_PRECISION (long_long_integer_type_node);
2016 :
2017 2087 : tree utype = unsigned_type_for (TREE_TYPE (src));
2018 2087 : src = fold_convert (utype, src);
2019 :
2020 2087 : if (direct_internal_fn_supported_p (IFN_POPCOUNT, utype, OPTIMIZE_FOR_BOTH))
2021 : use_ifn = true;
2022 2036 : else if (prec <= i_prec)
2023 1960 : fn = builtin_decl_implicit (BUILT_IN_POPCOUNT);
2024 76 : else if (prec == li_prec)
2025 59 : fn = builtin_decl_implicit (BUILT_IN_POPCOUNTL);
2026 17 : else if (prec == lli_prec || prec == 2 * lli_prec)
2027 17 : fn = builtin_decl_implicit (BUILT_IN_POPCOUNTLL);
2028 : else
2029 : return NULL_TREE;
2030 :
2031 51 : tree call;
2032 51 : if (use_ifn)
2033 51 : call = build_call_expr_internal_loc (UNKNOWN_LOCATION, IFN_POPCOUNT,
2034 : integer_type_node, 1, src);
2035 2036 : else if (prec == 2 * lli_prec)
2036 : {
2037 17 : tree src1 = fold_convert (long_long_unsigned_type_node,
2038 : fold_build2 (RSHIFT_EXPR, TREE_TYPE (src),
2039 : unshare_expr (src),
2040 : build_int_cst (integer_type_node,
2041 : lli_prec)));
2042 17 : tree src2 = fold_convert (long_long_unsigned_type_node, src);
2043 17 : tree call1 = build_call_expr (fn, 1, src1);
2044 17 : tree call2 = build_call_expr (fn, 1, src2);
2045 17 : call = fold_build2 (PLUS_EXPR, integer_type_node, call1, call2);
2046 : }
2047 : else
2048 : {
2049 2019 : if (prec < i_prec)
2050 291 : src = fold_convert (unsigned_type_node, src);
2051 :
2052 2019 : call = build_call_expr (fn, 1, src);
2053 : }
2054 :
2055 : return call;
2056 : }
2057 :
2058 : /* Utility function to check if OP is defined by a stmt
2059 : that is a val - 1. */
2060 :
2061 : static bool
2062 132097 : ssa_defined_by_minus_one_stmt_p (tree op, tree val)
2063 : {
2064 132097 : gimple *stmt;
2065 132097 : return (TREE_CODE (op) == SSA_NAME
2066 84585 : && (stmt = SSA_NAME_DEF_STMT (op))
2067 84585 : && is_gimple_assign (stmt)
2068 72700 : && (gimple_assign_rhs_code (stmt) == PLUS_EXPR)
2069 9152 : && val == gimple_assign_rhs1 (stmt)
2070 134434 : && integer_minus_onep (gimple_assign_rhs2 (stmt)));
2071 : }
2072 :
2073 : /* See comment below for number_of_iterations_bitcount.
2074 : For popcount, we have:
2075 :
2076 : modify:
2077 : _1 = iv_1 + -1
2078 : iv_2 = iv_1 & _1
2079 :
2080 : test:
2081 : if (iv != 0)
2082 :
2083 : modification count:
2084 : popcount (src)
2085 :
2086 : */
2087 :
2088 : static bool
2089 3721031 : number_of_iterations_popcount (loop_p loop, edge exit,
2090 : enum tree_code code,
2091 : class tree_niter_desc *niter)
2092 : {
2093 3721031 : bool modify_before_test = true;
2094 3721031 : HOST_WIDE_INT max;
2095 :
2096 : /* Check that condition for staying inside the loop is like
2097 : if (iv != 0). */
2098 7442062 : gcond *cond_stmt = safe_dyn_cast <gcond *> (*gsi_last_bb (exit->src));
2099 3721031 : if (!cond_stmt
2100 3721031 : || code != NE_EXPR
2101 1850932 : || !integer_zerop (gimple_cond_rhs (cond_stmt))
2102 5064217 : || TREE_CODE (gimple_cond_lhs (cond_stmt)) != SSA_NAME)
2103 2377845 : return false;
2104 :
2105 1343186 : tree iv_2 = gimple_cond_lhs (cond_stmt);
2106 1343186 : gimple *iv_2_stmt = SSA_NAME_DEF_STMT (iv_2);
2107 :
2108 : /* If the test comes before the iv modification, then these will actually be
2109 : iv_1 and a phi node. */
2110 1343186 : if (gimple_code (iv_2_stmt) == GIMPLE_PHI
2111 388819 : && gimple_bb (iv_2_stmt) == loop->header
2112 282101 : && gimple_phi_num_args (iv_2_stmt) == 2
2113 1625287 : && (TREE_CODE (gimple_phi_arg_def (iv_2_stmt,
2114 : loop_latch_edge (loop)->dest_idx))
2115 : == SSA_NAME))
2116 : {
2117 : /* iv_2 is actually one of the inputs to the phi. */
2118 263513 : iv_2 = gimple_phi_arg_def (iv_2_stmt, loop_latch_edge (loop)->dest_idx);
2119 263513 : iv_2_stmt = SSA_NAME_DEF_STMT (iv_2);
2120 263513 : modify_before_test = false;
2121 : }
2122 :
2123 : /* Make sure iv_2_stmt is an and stmt (iv_2 = _1 & iv_1). */
2124 1343186 : if (!is_gimple_assign (iv_2_stmt)
2125 1343186 : || gimple_assign_rhs_code (iv_2_stmt) != BIT_AND_EXPR)
2126 : return false;
2127 :
2128 66736 : tree iv_1 = gimple_assign_rhs1 (iv_2_stmt);
2129 66736 : tree _1 = gimple_assign_rhs2 (iv_2_stmt);
2130 :
2131 : /* Check that _1 is defined by (_1 = iv_1 + -1).
2132 : Also make sure that _1 is the same in and_stmt and _1 defining stmt.
2133 : Also canonicalize if _1 and _b11 are reversed. */
2134 66736 : if (ssa_defined_by_minus_one_stmt_p (iv_1, _1))
2135 : std::swap (iv_1, _1);
2136 65361 : else if (ssa_defined_by_minus_one_stmt_p (_1, iv_1))
2137 : ;
2138 : else
2139 : return false;
2140 :
2141 : /* Check the recurrence. */
2142 2106 : gimple *phi = SSA_NAME_DEF_STMT (iv_1);
2143 2106 : if (gimple_code (phi) != GIMPLE_PHI
2144 2106 : || (gimple_bb (phi) != loop_latch_edge (loop)->dest)
2145 4193 : || (iv_2 != gimple_phi_arg_def (phi, loop_latch_edge (loop)->dest_idx)))
2146 19 : return false;
2147 :
2148 : /* We found a match. */
2149 2087 : tree src = gimple_phi_arg_def (phi, loop_preheader_edge (loop)->dest_idx);
2150 2087 : int src_precision = TYPE_PRECISION (TREE_TYPE (src));
2151 :
2152 : /* Get the corresponding popcount builtin. */
2153 2087 : tree expr = build_popcount_expr (src);
2154 :
2155 2087 : if (!expr)
2156 : return false;
2157 :
2158 2087 : max = src_precision;
2159 :
2160 2087 : tree may_be_zero = boolean_false_node;
2161 :
2162 2087 : if (modify_before_test)
2163 : {
2164 984 : expr = fold_build2 (MINUS_EXPR, integer_type_node, expr,
2165 : integer_one_node);
2166 984 : max = max - 1;
2167 984 : may_be_zero = fold_build2 (EQ_EXPR, boolean_type_node, src,
2168 : build_zero_cst (TREE_TYPE (src)));
2169 : }
2170 :
2171 2087 : expr = fold_convert (unsigned_type_node, expr);
2172 :
2173 2087 : niter->assumptions = boolean_true_node;
2174 2087 : niter->may_be_zero = simplify_using_initial_conditions (loop, may_be_zero);
2175 2087 : niter->niter = simplify_using_initial_conditions(loop, expr);
2176 :
2177 2087 : if (TREE_CODE (niter->niter) == INTEGER_CST)
2178 195 : niter->max = tree_to_uhwi (niter->niter);
2179 : else
2180 1892 : niter->max = max;
2181 :
2182 2087 : niter->bound = NULL_TREE;
2183 2087 : niter->cmp = ERROR_MARK;
2184 2087 : return true;
2185 : }
2186 :
2187 : /* Return an expression that counts the leading/trailing zeroes of src.
2188 :
2189 : If define_at_zero is true, then the built expression will be defined to
2190 : return the precision of src when src == 0 (using either a conditional
2191 : expression or a suitable internal function).
2192 : Otherwise, we can elide the conditional expression and let src = 0 invoke
2193 : undefined behaviour. */
2194 :
2195 : static tree
2196 8744 : build_cltz_expr (tree src, bool leading, bool define_at_zero)
2197 : {
2198 8744 : tree fn;
2199 8744 : internal_fn ifn = leading ? IFN_CLZ : IFN_CTZ;
2200 8744 : bool use_ifn = false;
2201 8744 : int prec = TYPE_PRECISION (TREE_TYPE (src));
2202 8744 : int i_prec = TYPE_PRECISION (integer_type_node);
2203 8744 : int li_prec = TYPE_PRECISION (long_integer_type_node);
2204 8744 : int lli_prec = TYPE_PRECISION (long_long_integer_type_node);
2205 :
2206 8744 : tree utype = unsigned_type_for (TREE_TYPE (src));
2207 8744 : src = fold_convert (utype, src);
2208 :
2209 8744 : if (direct_internal_fn_supported_p (ifn, utype, OPTIMIZE_FOR_BOTH))
2210 : use_ifn = true;
2211 3439 : else if (prec <= i_prec)
2212 1650 : fn = leading ? builtin_decl_implicit (BUILT_IN_CLZ)
2213 3439 : : builtin_decl_implicit (BUILT_IN_CTZ);
2214 1789 : else if (prec == li_prec)
2215 0 : fn = leading ? builtin_decl_implicit (BUILT_IN_CLZL)
2216 3439 : : builtin_decl_implicit (BUILT_IN_CTZL);
2217 1789 : else if (prec == lli_prec || prec == 2 * lli_prec)
2218 1789 : fn = leading ? builtin_decl_implicit (BUILT_IN_CLZLL)
2219 3439 : : builtin_decl_implicit (BUILT_IN_CTZLL);
2220 : else
2221 : return NULL_TREE;
2222 :
2223 5305 : tree call;
2224 5305 : if (use_ifn)
2225 : {
2226 5305 : int val;
2227 5305 : int optab_defined_at_zero
2228 : = (leading
2229 5305 : ? CLZ_DEFINED_VALUE_AT_ZERO (SCALAR_INT_TYPE_MODE (utype), val)
2230 6176 : : CTZ_DEFINED_VALUE_AT_ZERO (SCALAR_INT_TYPE_MODE (utype), val));
2231 5305 : tree arg2 = NULL_TREE;
2232 5305 : if (define_at_zero && optab_defined_at_zero == 2 && val == prec)
2233 0 : arg2 = build_int_cst (integer_type_node, val);
2234 5305 : call = build_call_expr_internal_loc (UNKNOWN_LOCATION, ifn,
2235 : integer_type_node, arg2 ? 2 : 1,
2236 : src, arg2);
2237 5305 : if (define_at_zero && arg2 == NULL_TREE)
2238 : {
2239 4459 : tree is_zero = fold_build2 (NE_EXPR, boolean_type_node, src,
2240 : build_zero_cst (TREE_TYPE (src)));
2241 4459 : call = fold_build3 (COND_EXPR, integer_type_node, is_zero, call,
2242 : build_int_cst (integer_type_node, prec));
2243 : }
2244 : }
2245 3439 : else if (fn == NULL_TREE)
2246 : return NULL_TREE;
2247 3439 : else if (prec == 2 * lli_prec)
2248 : {
2249 854 : tree src1 = fold_convert (long_long_unsigned_type_node,
2250 : fold_build2 (RSHIFT_EXPR, TREE_TYPE (src),
2251 : unshare_expr (src),
2252 : build_int_cst (integer_type_node,
2253 : lli_prec)));
2254 854 : tree src2 = fold_convert (long_long_unsigned_type_node, src);
2255 : /* We count the zeroes in src1, and add the number in src2 when src1
2256 : is 0. */
2257 854 : if (!leading)
2258 10 : std::swap (src1, src2);
2259 854 : tree call1 = build_call_expr (fn, 1, src1);
2260 854 : tree call2 = build_call_expr (fn, 1, src2);
2261 854 : if (define_at_zero)
2262 : {
2263 728 : tree is_zero2 = fold_build2 (NE_EXPR, boolean_type_node, src2,
2264 : build_zero_cst (TREE_TYPE (src2)));
2265 728 : call2 = fold_build3 (COND_EXPR, integer_type_node, is_zero2, call2,
2266 : build_int_cst (integer_type_node, lli_prec));
2267 : }
2268 854 : tree is_zero1 = fold_build2 (NE_EXPR, boolean_type_node, src1,
2269 : build_zero_cst (TREE_TYPE (src1)));
2270 854 : call = fold_build3 (COND_EXPR, integer_type_node, is_zero1, call1,
2271 : fold_build2 (PLUS_EXPR, integer_type_node, call2,
2272 : build_int_cst (integer_type_node,
2273 : lli_prec)));
2274 : }
2275 : else
2276 : {
2277 2585 : if (prec < i_prec)
2278 1650 : src = fold_convert (unsigned_type_node, src);
2279 :
2280 2585 : call = build_call_expr (fn, 1, src);
2281 2585 : if (leading && prec < i_prec)
2282 1547 : call = fold_build2 (MINUS_EXPR, integer_type_node, call,
2283 : build_int_cst (integer_type_node, i_prec - prec));
2284 2585 : if (define_at_zero)
2285 : {
2286 2388 : tree is_zero = fold_build2 (NE_EXPR, boolean_type_node, src,
2287 : build_zero_cst (TREE_TYPE (src)));
2288 2388 : call = fold_build3 (COND_EXPR, integer_type_node, is_zero, call,
2289 : build_int_cst (integer_type_node, prec));
2290 : }
2291 : }
2292 :
2293 : return call;
2294 : }
2295 :
2296 : /* Returns true if STMT is equivalent to x << 1. */
2297 :
2298 : static bool
2299 1114308 : is_lshift_by_1 (gassign *stmt)
2300 : {
2301 1114308 : if (gimple_assign_rhs_code (stmt) == LSHIFT_EXPR
2302 1115594 : && integer_onep (gimple_assign_rhs2 (stmt)))
2303 : return true;
2304 1113569 : if (gimple_assign_rhs_code (stmt) == MULT_EXPR
2305 1300 : && tree_fits_shwi_p (gimple_assign_rhs2 (stmt))
2306 1114550 : && tree_to_shwi (gimple_assign_rhs2 (stmt)) == 2)
2307 : return true;
2308 : return false;
2309 : }
2310 :
2311 : /* Returns true if STMT is equivalent to x >> 1. */
2312 :
2313 : static bool
2314 1113336 : is_rshift_by_1 (gassign *stmt)
2315 : {
2316 1113336 : if (!TYPE_UNSIGNED (TREE_TYPE (gimple_assign_lhs (stmt))))
2317 : return false;
2318 808447 : if (gimple_assign_rhs_code (stmt) == RSHIFT_EXPR
2319 827929 : && integer_onep (gimple_assign_rhs2 (stmt)))
2320 : return true;
2321 1506721 : if (trunc_or_exact_div_p (gimple_assign_rhs_code (stmt))
2322 575 : && tree_fits_shwi_p (gimple_assign_rhs2 (stmt))
2323 799107 : && tree_to_shwi (gimple_assign_rhs2 (stmt)) == 2)
2324 : return true;
2325 : return false;
2326 : }
2327 :
2328 : /* Helper for number_of_iterations_cltz that uses ranger to determine
2329 : if SRC's range, shifted left (when LEFT_SHIFT is true) or right
2330 : by NUM_IGNORED_BITS, is guaranteed to be != 0 on LOOP's preheader
2331 : edge.
2332 : Return true if so or false otherwise. */
2333 :
2334 : static bool
2335 1169 : shifted_range_nonzero_p (loop_p loop, tree src,
2336 : bool left_shift, int num_ignored_bits)
2337 : {
2338 1169 : int_range_max r (TREE_TYPE (src));
2339 1169 : gcc_assert (num_ignored_bits >= 0);
2340 :
2341 1169 : if (get_range_query (cfun)->range_on_edge
2342 1169 : (r, loop_preheader_edge (loop), src)
2343 1169 : && !r.varying_p ()
2344 1718 : && !r.undefined_p ())
2345 : {
2346 548 : if (num_ignored_bits)
2347 : {
2348 572 : range_op_handler op (left_shift ? LSHIFT_EXPR : RSHIFT_EXPR);
2349 384 : int_range_max shifted_range (TREE_TYPE (src));
2350 384 : wide_int shift_count = wi::shwi (num_ignored_bits,
2351 384 : TYPE_PRECISION (TREE_TYPE
2352 384 : (src)));
2353 384 : int_range_max shift_amount
2354 384 : (TREE_TYPE (src), shift_count, shift_count);
2355 :
2356 384 : if (op.fold_range (shifted_range, TREE_TYPE (src), r,
2357 : shift_amount))
2358 384 : r = shifted_range;
2359 384 : }
2360 :
2361 : /* If the range does not contain zero we are good. */
2362 548 : if (!range_includes_zero_p (r))
2363 : return true;
2364 : }
2365 :
2366 : return false;
2367 1169 : }
2368 :
2369 :
2370 : /* See comment below for number_of_iterations_bitcount.
2371 : For c[lt]z, we have:
2372 :
2373 : modify:
2374 : iv_2 = iv_1 << 1 OR iv_1 >> 1
2375 :
2376 : test:
2377 : if (iv & 1 << (prec-1)) OR (iv & 1)
2378 :
2379 : modification count:
2380 : src precision - c[lt]z (src)
2381 :
2382 : */
2383 :
2384 : static bool
2385 6827499 : number_of_iterations_cltz (loop_p loop, edge exit,
2386 : enum tree_code code,
2387 : class tree_niter_desc *niter)
2388 : {
2389 6827499 : bool modify_before_test = true;
2390 6827499 : HOST_WIDE_INT max;
2391 6827499 : int checked_bit;
2392 6827499 : tree iv_2;
2393 :
2394 : /* Check that condition for staying inside the loop is like
2395 : if (iv == 0). */
2396 13654998 : gcond *cond_stmt = safe_dyn_cast <gcond *> (*gsi_last_bb (exit->src));
2397 6827499 : if (!cond_stmt
2398 6827499 : || (code != EQ_EXPR && code != GE_EXPR)
2399 3404557 : || !integer_zerop (gimple_cond_rhs (cond_stmt))
2400 1314710 : || TREE_CODE (gimple_cond_lhs (cond_stmt)) != SSA_NAME)
2401 5512978 : return false;
2402 :
2403 1314521 : if (code == EQ_EXPR)
2404 : {
2405 : /* Make sure we check a bitwise and with a suitable constant */
2406 1191061 : gimple *and_stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (cond_stmt));
2407 1191061 : if (!is_gimple_assign (and_stmt)
2408 716055 : || gimple_assign_rhs_code (and_stmt) != BIT_AND_EXPR
2409 131953 : || !integer_pow2p (gimple_assign_rhs2 (and_stmt))
2410 1209162 : || TREE_CODE (gimple_assign_rhs1 (and_stmt)) != SSA_NAME)
2411 1172960 : return false;
2412 :
2413 18101 : checked_bit = tree_log2 (gimple_assign_rhs2 (and_stmt));
2414 :
2415 18101 : iv_2 = gimple_assign_rhs1 (and_stmt);
2416 : }
2417 : else
2418 : {
2419 : /* We have a GE_EXPR - a signed comparison with zero is equivalent to
2420 : testing the leading bit, so check for this pattern too. */
2421 :
2422 123460 : iv_2 = gimple_cond_lhs (cond_stmt);
2423 123460 : tree test_value_type = TREE_TYPE (iv_2);
2424 :
2425 123460 : if (TYPE_UNSIGNED (test_value_type))
2426 : return false;
2427 :
2428 123460 : gimple *test_value_stmt = SSA_NAME_DEF_STMT (iv_2);
2429 :
2430 123460 : if (is_gimple_assign (test_value_stmt)
2431 123460 : && gimple_assign_rhs_code (test_value_stmt) == NOP_EXPR)
2432 : {
2433 : /* If the test value comes from a NOP_EXPR, then we need to unwrap
2434 : this. We conservatively require that both types have the same
2435 : precision. */
2436 5194 : iv_2 = gimple_assign_rhs1 (test_value_stmt);
2437 5194 : tree rhs_type = TREE_TYPE (iv_2);
2438 5194 : if (TREE_CODE (iv_2) != SSA_NAME
2439 5194 : || !INTEGRAL_NB_TYPE_P (rhs_type)
2440 10377 : || (TYPE_PRECISION (rhs_type)
2441 5183 : != TYPE_PRECISION (test_value_type)))
2442 : return false;
2443 : }
2444 :
2445 123060 : checked_bit = TYPE_PRECISION (test_value_type) - 1;
2446 : }
2447 :
2448 141161 : gimple *iv_2_stmt = SSA_NAME_DEF_STMT (iv_2);
2449 :
2450 : /* If the test comes before the iv modification, then these will actually be
2451 : iv_1 and a phi node. */
2452 141161 : if (gimple_code (iv_2_stmt) == GIMPLE_PHI
2453 26274 : && gimple_bb (iv_2_stmt) == loop->header
2454 15173 : && gimple_phi_num_args (iv_2_stmt) == 2
2455 156334 : && (TREE_CODE (gimple_phi_arg_def (iv_2_stmt,
2456 : loop_latch_edge (loop)->dest_idx))
2457 : == SSA_NAME))
2458 : {
2459 : /* iv_2 is actually one of the inputs to the phi. */
2460 14979 : iv_2 = gimple_phi_arg_def (iv_2_stmt, loop_latch_edge (loop)->dest_idx);
2461 14979 : iv_2_stmt = SSA_NAME_DEF_STMT (iv_2);
2462 14979 : modify_before_test = false;
2463 : }
2464 :
2465 : /* Make sure iv_2_stmt is a logical shift by one stmt:
2466 : iv_2 = iv_1 {<<|>>} 1 */
2467 141161 : if (!is_gimple_assign (iv_2_stmt))
2468 : return false;
2469 111123 : bool left_shift = false;
2470 221738 : if (!((left_shift = is_lshift_by_1 (as_a <gassign *> (iv_2_stmt)))
2471 110615 : || is_rshift_by_1 (as_a <gassign *> (iv_2_stmt))))
2472 : return false;
2473 :
2474 1212 : tree iv_1 = gimple_assign_rhs1 (iv_2_stmt);
2475 :
2476 : /* Check the recurrence. */
2477 1212 : gimple *phi = SSA_NAME_DEF_STMT (iv_1);
2478 1212 : if (gimple_code (phi) != GIMPLE_PHI
2479 1175 : || (gimple_bb (phi) != loop_latch_edge (loop)->dest)
2480 2381 : || (iv_2 != gimple_phi_arg_def (phi, loop_latch_edge (loop)->dest_idx)))
2481 43 : return false;
2482 :
2483 : /* We found a match. */
2484 1169 : tree src = gimple_phi_arg_def (phi, loop_preheader_edge (loop)->dest_idx);
2485 1169 : int src_precision = TYPE_PRECISION (TREE_TYPE (src));
2486 :
2487 : /* Save the original SSA name before preprocessing for ranger queries. */
2488 1169 : tree unshifted_src = src;
2489 :
2490 : /* Apply any needed preprocessing to src. */
2491 1169 : int num_ignored_bits;
2492 1169 : if (left_shift)
2493 465 : num_ignored_bits = src_precision - checked_bit - 1;
2494 : else
2495 : num_ignored_bits = checked_bit;
2496 :
2497 1169 : if (modify_before_test)
2498 506 : num_ignored_bits++;
2499 :
2500 1169 : if (num_ignored_bits != 0)
2501 1102 : src = fold_build2 (left_shift ? LSHIFT_EXPR : RSHIFT_EXPR,
2502 : TREE_TYPE (src), src,
2503 : build_int_cst (integer_type_node, num_ignored_bits));
2504 :
2505 : /* Get the corresponding c[lt]z builtin. */
2506 1169 : tree expr = build_cltz_expr (src, left_shift, false);
2507 :
2508 1169 : if (!expr)
2509 : return false;
2510 :
2511 1169 : max = src_precision - num_ignored_bits - 1;
2512 :
2513 1169 : expr = fold_convert (unsigned_type_node, expr);
2514 :
2515 : /* If the copy-header (ch) pass peeled one iteration we're shifting
2516 : SRC by preprocessing it above.
2517 :
2518 : A loop like
2519 : if (bits)
2520 : {
2521 : while (!(bits & 1))
2522 : {
2523 : bits >>= 1;
2524 : cnt += 1;
2525 : }
2526 : return cnt;
2527 : }
2528 : ch (roughly) transforms into:
2529 : if (bits)
2530 : {
2531 : if (!(bits & 1)
2532 : {
2533 : do
2534 : {
2535 : bits >>= 1;
2536 : cnt += 1;
2537 : } while (!(bits & 1));
2538 : }
2539 : else
2540 : cnt = 1;
2541 : return cnt;
2542 : }
2543 :
2544 : Then, our preprocessed SRC (that is used for c[tl]z computation)
2545 : will be bits >> 1, and the assumption is bits >> 1 != 0. */
2546 :
2547 1169 : tree assumptions;
2548 1169 : if (shifted_range_nonzero_p (loop, unshifted_src,
2549 : left_shift, num_ignored_bits))
2550 257 : assumptions = boolean_true_node;
2551 : else
2552 : {
2553 : /* If ranger couldn't prove the assumption, try
2554 : simplify_using_initial_conditions. */
2555 912 : assumptions = fold_build2 (NE_EXPR, boolean_type_node, src,
2556 : build_zero_cst (TREE_TYPE (src)));
2557 912 : assumptions = simplify_using_initial_conditions (loop, assumptions);
2558 : }
2559 :
2560 1169 : niter->assumptions = assumptions;
2561 1169 : niter->may_be_zero = boolean_false_node;
2562 1169 : niter->niter = simplify_using_initial_conditions (loop, expr);
2563 :
2564 1169 : if (TREE_CODE (niter->niter) == INTEGER_CST)
2565 0 : niter->max = tree_to_uhwi (niter->niter);
2566 : else
2567 1169 : niter->max = max;
2568 :
2569 1169 : niter->bound = NULL_TREE;
2570 1169 : niter->cmp = ERROR_MARK;
2571 :
2572 1169 : return true;
2573 : }
2574 :
2575 : /* See comment below for number_of_iterations_bitcount.
2576 : For c[lt]z complement, we have:
2577 :
2578 : modify:
2579 : iv_2 = iv_1 >> 1 OR iv_1 << 1
2580 :
2581 : test:
2582 : if (iv != 0)
2583 :
2584 : modification count:
2585 : src precision - c[lt]z (src)
2586 :
2587 : */
2588 :
2589 : static bool
2590 3718775 : number_of_iterations_cltz_complement (loop_p loop, edge exit,
2591 : enum tree_code code,
2592 : class tree_niter_desc *niter)
2593 : {
2594 3718775 : bool modify_before_test = true;
2595 3718775 : HOST_WIDE_INT max;
2596 :
2597 : /* Check that condition for staying inside the loop is like
2598 : if (iv != 0). */
2599 7437550 : gcond *cond_stmt = safe_dyn_cast <gcond *> (*gsi_last_bb (exit->src));
2600 3718775 : if (!cond_stmt
2601 3718775 : || code != NE_EXPR
2602 1848845 : || !integer_zerop (gimple_cond_rhs (cond_stmt))
2603 5059874 : || TREE_CODE (gimple_cond_lhs (cond_stmt)) != SSA_NAME)
2604 2377676 : return false;
2605 :
2606 1341099 : tree iv_2 = gimple_cond_lhs (cond_stmt);
2607 1341099 : gimple *iv_2_stmt = SSA_NAME_DEF_STMT (iv_2);
2608 :
2609 : /* If the test comes before the iv modification, then these will actually be
2610 : iv_1 and a phi node. */
2611 1341099 : if (gimple_code (iv_2_stmt) == GIMPLE_PHI
2612 387716 : && gimple_bb (iv_2_stmt) == loop->header
2613 280998 : && gimple_phi_num_args (iv_2_stmt) == 2
2614 1622097 : && (TREE_CODE (gimple_phi_arg_def (iv_2_stmt,
2615 : loop_latch_edge (loop)->dest_idx))
2616 : == SSA_NAME))
2617 : {
2618 : /* iv_2 is actually one of the inputs to the phi. */
2619 262410 : iv_2 = gimple_phi_arg_def (iv_2_stmt, loop_latch_edge (loop)->dest_idx);
2620 262410 : iv_2_stmt = SSA_NAME_DEF_STMT (iv_2);
2621 262410 : modify_before_test = false;
2622 : }
2623 :
2624 : /* Make sure iv_2_stmt is a logical shift by one stmt:
2625 : iv_2 = iv_1 {>>|<<} 1 */
2626 1341099 : if (!is_gimple_assign (iv_2_stmt))
2627 : return false;
2628 1003185 : bool left_shift = false;
2629 2005906 : if (!((left_shift = is_lshift_by_1 (as_a <gassign *> (iv_2_stmt)))
2630 1002721 : || is_rshift_by_1 (as_a <gassign *> (iv_2_stmt))))
2631 : return false;
2632 :
2633 9616 : tree iv_1 = gimple_assign_rhs1 (iv_2_stmt);
2634 :
2635 : /* Check the recurrence. */
2636 9616 : gimple *phi = SSA_NAME_DEF_STMT (iv_1);
2637 9616 : if (gimple_code (phi) != GIMPLE_PHI
2638 8961 : || (gimple_bb (phi) != loop_latch_edge (loop)->dest)
2639 17409 : || (iv_2 != gimple_phi_arg_def (phi, loop_latch_edge (loop)->dest_idx)))
2640 2041 : return false;
2641 :
2642 : /* We found a match. */
2643 7575 : tree src = gimple_phi_arg_def (phi, loop_preheader_edge (loop)->dest_idx);
2644 7575 : int src_precision = TYPE_PRECISION (TREE_TYPE (src));
2645 :
2646 : /* Get the corresponding c[lt]z builtin. */
2647 7575 : tree expr = build_cltz_expr (src, !left_shift, true);
2648 :
2649 7575 : if (!expr)
2650 : return false;
2651 :
2652 7575 : expr = fold_build2 (MINUS_EXPR, integer_type_node,
2653 : build_int_cst (integer_type_node, src_precision),
2654 : expr);
2655 :
2656 7575 : max = src_precision;
2657 :
2658 7575 : tree may_be_zero = boolean_false_node;
2659 :
2660 7575 : if (modify_before_test)
2661 : {
2662 6315 : expr = fold_build2 (MINUS_EXPR, integer_type_node, expr,
2663 : integer_one_node);
2664 6315 : max = max - 1;
2665 6315 : may_be_zero = fold_build2 (EQ_EXPR, boolean_type_node, src,
2666 : build_zero_cst (TREE_TYPE (src)));
2667 : }
2668 :
2669 7575 : expr = fold_convert (unsigned_type_node, expr);
2670 :
2671 7575 : niter->assumptions = boolean_true_node;
2672 7575 : niter->may_be_zero = simplify_using_initial_conditions (loop, may_be_zero);
2673 7575 : niter->niter = simplify_using_initial_conditions (loop, expr);
2674 :
2675 7575 : if (TREE_CODE (niter->niter) == INTEGER_CST)
2676 69 : niter->max = tree_to_uhwi (niter->niter);
2677 : else
2678 7506 : niter->max = max;
2679 :
2680 7575 : niter->bound = NULL_TREE;
2681 7575 : niter->cmp = ERROR_MARK;
2682 7575 : return true;
2683 : }
2684 :
2685 : /* See if LOOP contains a bit counting idiom. The idiom consists of two parts:
2686 : 1. A modification to the induction variabler;.
2687 : 2. A test to determine whether or not to exit the loop.
2688 :
2689 : These can come in either order - i.e.:
2690 :
2691 : <bb 3>
2692 : iv_1 = PHI <src(2), iv_2(4)>
2693 : if (test (iv_1))
2694 : goto <bb 4>
2695 : else
2696 : goto <bb 5>
2697 :
2698 : <bb 4>
2699 : iv_2 = modify (iv_1)
2700 : goto <bb 3>
2701 :
2702 : OR
2703 :
2704 : <bb 3>
2705 : iv_1 = PHI <src(2), iv_2(4)>
2706 : iv_2 = modify (iv_1)
2707 :
2708 : <bb 4>
2709 : if (test (iv_2))
2710 : goto <bb 3>
2711 : else
2712 : goto <bb 5>
2713 :
2714 : The second form can be generated by copying the loop header out of the loop.
2715 :
2716 : In the first case, the number of latch executions will be equal to the
2717 : number of induction variable modifications required before the test fails.
2718 :
2719 : In the second case (modify_before_test), if we assume that the number of
2720 : modifications required before the test fails is nonzero, then the number of
2721 : latch executions will be one less than this number.
2722 :
2723 : If we recognise the pattern, then we update niter accordingly, and return
2724 : true. */
2725 :
2726 : static bool
2727 3721031 : number_of_iterations_bitcount (loop_p loop, edge exit,
2728 : enum tree_code code,
2729 : class tree_niter_desc *niter)
2730 : {
2731 3721031 : return (number_of_iterations_popcount (loop, exit, code, niter)
2732 3718944 : || number_of_iterations_cltz (loop, exit, code, niter)
2733 7439806 : || number_of_iterations_cltz_complement (loop, exit, code, niter));
2734 : }
2735 :
2736 : /* Substitute NEW_TREE for OLD in EXPR and fold the result.
2737 : If VALUEIZE is non-NULL then OLD and NEW_TREE are ignored and instead
2738 : all SSA names are replaced with the result of calling the VALUEIZE
2739 : function with the SSA name as argument. */
2740 :
2741 : tree
2742 154179009 : simplify_replace_tree (tree expr, tree old, tree new_tree,
2743 : tree (*valueize) (tree, void*), void *context,
2744 : bool do_fold)
2745 : {
2746 154179009 : unsigned i, n;
2747 154179009 : tree ret = NULL_TREE, e, se;
2748 :
2749 154179009 : if (!expr)
2750 : return NULL_TREE;
2751 :
2752 : /* Do not bother to replace constants. */
2753 31101854 : if (CONSTANT_CLASS_P (expr))
2754 : return expr;
2755 :
2756 23532871 : if (valueize)
2757 : {
2758 273004 : if (TREE_CODE (expr) == SSA_NAME)
2759 : {
2760 84493 : new_tree = valueize (expr, context);
2761 84493 : if (new_tree != expr)
2762 : return new_tree;
2763 : }
2764 : }
2765 23259867 : else if (expr == old
2766 23259867 : || operand_equal_p (expr, old, 0))
2767 218160 : return unshare_expr (new_tree);
2768 :
2769 23314181 : if (!EXPR_P (expr))
2770 : return expr;
2771 :
2772 12474207 : n = TREE_OPERAND_LENGTH (expr);
2773 34974092 : for (i = 0; i < n; i++)
2774 : {
2775 22499885 : e = TREE_OPERAND (expr, i);
2776 22499885 : se = simplify_replace_tree (e, old, new_tree, valueize, context, do_fold);
2777 22499885 : if (e == se)
2778 22221199 : continue;
2779 :
2780 278686 : if (!ret)
2781 278123 : ret = copy_node (expr);
2782 :
2783 278686 : TREE_OPERAND (ret, i) = se;
2784 : }
2785 :
2786 12474207 : return (ret ? (do_fold ? fold (ret) : ret) : expr);
2787 : }
2788 :
2789 : /* Expand definitions of ssa names in EXPR as long as they are simple
2790 : enough, and return the new expression. If STOP is specified, stop
2791 : expanding if EXPR equals to it. */
2792 :
2793 : static tree
2794 122527610 : expand_simple_operations (tree expr, tree stop, hash_map<tree, tree> &cache)
2795 : {
2796 122969481 : unsigned i, n;
2797 122969481 : tree ret = NULL_TREE, e, ee, e1;
2798 122969481 : enum tree_code code;
2799 122969481 : gimple *stmt;
2800 :
2801 122969481 : if (expr == NULL_TREE)
2802 : return expr;
2803 :
2804 122969481 : if (is_gimple_min_invariant (expr))
2805 : return expr;
2806 :
2807 84318681 : code = TREE_CODE (expr);
2808 84318681 : if (IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (code)))
2809 : {
2810 20197141 : n = TREE_OPERAND_LENGTH (expr);
2811 55840152 : for (i = 0; i < n; i++)
2812 : {
2813 35643011 : e = TREE_OPERAND (expr, i);
2814 35643011 : if (!e)
2815 32305391 : continue;
2816 : /* SCEV analysis feeds us with a proper expression
2817 : graph matching the SSA graph. Avoid turning it
2818 : into a tree here, thus handle tree sharing
2819 : properly.
2820 : ??? The SSA walk below still turns the SSA graph
2821 : into a tree but until we find a testcase do not
2822 : introduce additional tree sharing here. */
2823 35626217 : bool existed_p;
2824 35626217 : tree &cee = cache.get_or_insert (e, &existed_p);
2825 35626217 : if (existed_p)
2826 150677 : ee = cee;
2827 : else
2828 : {
2829 35475540 : cee = e;
2830 35475540 : ee = expand_simple_operations (e, stop, cache);
2831 35475540 : if (ee != e)
2832 3335782 : *cache.get (e) = ee;
2833 : }
2834 35626217 : if (e == ee)
2835 32288597 : continue;
2836 :
2837 3337620 : if (!ret)
2838 3170615 : ret = copy_node (expr);
2839 :
2840 3337620 : TREE_OPERAND (ret, i) = ee;
2841 : }
2842 :
2843 20197141 : if (!ret)
2844 : return expr;
2845 :
2846 3170615 : ret = fold (ret);
2847 3170615 : return ret;
2848 : }
2849 :
2850 : /* Stop if it's not ssa name or the one we don't want to expand. */
2851 64121540 : if (TREE_CODE (expr) != SSA_NAME || expr == stop)
2852 : return expr;
2853 :
2854 63923351 : stmt = SSA_NAME_DEF_STMT (expr);
2855 63923351 : if (gimple_code (stmt) == GIMPLE_PHI)
2856 : {
2857 17241221 : basic_block src, dest;
2858 :
2859 17241221 : if (gimple_phi_num_args (stmt) != 1)
2860 : return expr;
2861 591358 : e = PHI_ARG_DEF (stmt, 0);
2862 :
2863 : /* Avoid propagating through loop exit phi nodes, which
2864 : could break loop-closed SSA form restrictions. */
2865 591358 : dest = gimple_bb (stmt);
2866 591358 : src = single_pred (dest);
2867 591358 : if (TREE_CODE (e) == SSA_NAME
2868 589538 : && src->loop_father != dest->loop_father)
2869 : return expr;
2870 :
2871 : return expand_simple_operations (e, stop, cache);
2872 : }
2873 46682130 : if (gimple_code (stmt) != GIMPLE_ASSIGN)
2874 : return expr;
2875 :
2876 : /* Avoid expanding to expressions that contain SSA names that need
2877 : to take part in abnormal coalescing. */
2878 41202177 : ssa_op_iter iter;
2879 85650586 : FOR_EACH_SSA_TREE_OPERAND (e, stmt, iter, SSA_OP_USE)
2880 44449005 : if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (e))
2881 : return expr;
2882 :
2883 41201581 : e = gimple_assign_rhs1 (stmt);
2884 41201581 : code = gimple_assign_rhs_code (stmt);
2885 41201581 : if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS)
2886 : {
2887 16055479 : if (is_gimple_min_invariant (e))
2888 : return e;
2889 :
2890 16013339 : if (code == SSA_NAME)
2891 : return expand_simple_operations (e, stop, cache);
2892 15798121 : else if (code == ADDR_EXPR)
2893 : {
2894 14640 : poly_int64 offset;
2895 14640 : tree base = get_addr_base_and_unit_offset (TREE_OPERAND (e, 0),
2896 : &offset);
2897 14640 : if (base
2898 14366 : && TREE_CODE (base) == MEM_REF)
2899 : {
2900 14366 : ee = expand_simple_operations (TREE_OPERAND (base, 0), stop,
2901 : cache);
2902 14366 : return fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (expr), ee,
2903 : wide_int_to_tree (sizetype,
2904 : mem_ref_offset (base)
2905 : + offset));
2906 : }
2907 : }
2908 :
2909 15783755 : return expr;
2910 : }
2911 :
2912 25146102 : switch (code)
2913 : {
2914 6292723 : CASE_CONVERT:
2915 : /* Casts are simple. */
2916 6292723 : ee = expand_simple_operations (e, stop, cache);
2917 6292723 : return fold_build1 (code, TREE_TYPE (expr), ee);
2918 :
2919 13762974 : case PLUS_EXPR:
2920 13762974 : case MINUS_EXPR:
2921 13762974 : case MULT_EXPR:
2922 27525948 : if (ANY_INTEGRAL_TYPE_P (TREE_TYPE (expr))
2923 27523367 : && TYPE_OVERFLOW_TRAPS (TREE_TYPE (expr)))
2924 : return expr;
2925 : /* Fallthru. */
2926 14463170 : case POINTER_PLUS_EXPR:
2927 : /* And increments and decrements by a constant are simple. */
2928 14463170 : e1 = gimple_assign_rhs2 (stmt);
2929 14463170 : if (!is_gimple_min_invariant (e1))
2930 : return expr;
2931 :
2932 7530178 : ee = expand_simple_operations (e, stop, cache);
2933 7530178 : return fold_build2 (code, TREE_TYPE (expr), ee, e1);
2934 :
2935 : default:
2936 : return expr;
2937 : }
2938 : }
2939 :
2940 : tree
2941 73214803 : expand_simple_operations (tree expr, tree stop)
2942 : {
2943 73214803 : hash_map<tree, tree> cache;
2944 73214803 : return expand_simple_operations (expr, stop, cache);
2945 73214803 : }
2946 :
2947 : /* Tries to simplify EXPR using the condition COND. Returns the simplified
2948 : expression (or EXPR unchanged, if no simplification was possible). */
2949 :
2950 : static tree
2951 8912091 : tree_simplify_using_condition_1 (tree cond, tree expr)
2952 : {
2953 8912091 : bool changed;
2954 8912091 : tree e, e0, e1, e2, notcond;
2955 8912091 : enum tree_code code = TREE_CODE (expr);
2956 :
2957 8912091 : if (code == INTEGER_CST)
2958 : return expr;
2959 :
2960 8901891 : if (code == TRUTH_OR_EXPR
2961 8901891 : || code == TRUTH_AND_EXPR
2962 8901891 : || code == COND_EXPR)
2963 : {
2964 111805 : changed = false;
2965 :
2966 111805 : e0 = tree_simplify_using_condition_1 (cond, TREE_OPERAND (expr, 0));
2967 111805 : if (TREE_OPERAND (expr, 0) != e0)
2968 2085 : changed = true;
2969 :
2970 111805 : e1 = tree_simplify_using_condition_1 (cond, TREE_OPERAND (expr, 1));
2971 111805 : if (TREE_OPERAND (expr, 1) != e1)
2972 0 : changed = true;
2973 :
2974 111805 : if (code == COND_EXPR)
2975 : {
2976 12124 : e2 = tree_simplify_using_condition_1 (cond, TREE_OPERAND (expr, 2));
2977 12124 : if (TREE_OPERAND (expr, 2) != e2)
2978 : changed = true;
2979 : }
2980 : else
2981 : e2 = NULL_TREE;
2982 :
2983 111805 : if (changed)
2984 : {
2985 2085 : if (code == COND_EXPR)
2986 1948 : expr = fold_build3 (code, boolean_type_node, e0, e1, e2);
2987 : else
2988 137 : expr = fold_build2 (code, boolean_type_node, e0, e1);
2989 : }
2990 :
2991 111805 : return expr;
2992 : }
2993 :
2994 : /* In case COND is equality, we may be able to simplify EXPR by copy/constant
2995 : propagation, and vice versa. Fold does not handle this, since it is
2996 : considered too expensive. */
2997 8790086 : if (TREE_CODE (cond) == EQ_EXPR)
2998 : {
2999 2083115 : e0 = TREE_OPERAND (cond, 0);
3000 2083115 : e1 = TREE_OPERAND (cond, 1);
3001 :
3002 : /* We know that e0 == e1. Check whether we cannot simplify expr
3003 : using this fact. */
3004 2083115 : e = simplify_replace_tree (expr, e0, e1);
3005 2083115 : if (integer_zerop (e) || integer_nonzerop (e))
3006 2184 : return e;
3007 :
3008 2080931 : e = simplify_replace_tree (expr, e1, e0);
3009 2080931 : if (integer_zerop (e) || integer_nonzerop (e))
3010 411 : return e;
3011 : }
3012 8787491 : if (TREE_CODE (expr) == EQ_EXPR)
3013 : {
3014 1048476 : e0 = TREE_OPERAND (expr, 0);
3015 1048476 : e1 = TREE_OPERAND (expr, 1);
3016 :
3017 : /* If e0 == e1 (EXPR) implies !COND, then EXPR cannot be true. */
3018 1048476 : e = simplify_replace_tree (cond, e0, e1);
3019 1048476 : if (integer_zerop (e))
3020 : return e;
3021 1034367 : e = simplify_replace_tree (cond, e1, e0);
3022 1034367 : if (integer_zerop (e))
3023 : return e;
3024 : }
3025 8773382 : if (TREE_CODE (expr) == NE_EXPR)
3026 : {
3027 1060639 : e0 = TREE_OPERAND (expr, 0);
3028 1060639 : e1 = TREE_OPERAND (expr, 1);
3029 :
3030 : /* If e0 == e1 (!EXPR) implies !COND, then EXPR must be true. */
3031 1060639 : e = simplify_replace_tree (cond, e0, e1);
3032 1060639 : if (integer_zerop (e))
3033 12702 : return boolean_true_node;
3034 1047937 : e = simplify_replace_tree (cond, e1, e0);
3035 1047937 : if (integer_zerop (e))
3036 0 : return boolean_true_node;
3037 : }
3038 :
3039 : /* Check whether COND ==> EXPR. */
3040 8760680 : notcond = invert_truthvalue (cond);
3041 8760680 : e = fold_binary (TRUTH_OR_EXPR, boolean_type_node, notcond, expr);
3042 8760680 : if (e && integer_nonzerop (e))
3043 : return e;
3044 :
3045 : /* Check whether COND ==> not EXPR. */
3046 8758438 : e = fold_binary (TRUTH_AND_EXPR, boolean_type_node, cond, expr);
3047 8758438 : if (e && integer_zerop (e))
3048 : return e;
3049 :
3050 : return expr;
3051 : }
3052 :
3053 : /* Tries to simplify EXPR using the condition COND. Returns the simplified
3054 : expression (or EXPR unchanged, if no simplification was possible).
3055 : Wrapper around tree_simplify_using_condition_1 that ensures that chains
3056 : of simple operations in definitions of ssa names in COND are expanded,
3057 : so that things like casts or incrementing the value of the bound before
3058 : the loop do not cause us to fail. */
3059 :
3060 : static tree
3061 8676357 : tree_simplify_using_condition (tree cond, tree expr)
3062 : {
3063 8676357 : cond = expand_simple_operations (cond);
3064 :
3065 8676357 : return tree_simplify_using_condition_1 (cond, expr);
3066 : }
3067 :
3068 : /* Tries to simplify EXPR using the conditions on entry to LOOP.
3069 : Returns the simplified expression (or EXPR unchanged, if no
3070 : simplification was possible). */
3071 :
3072 : tree
3073 27966513 : simplify_using_initial_conditions (class loop *loop, tree expr)
3074 : {
3075 27966513 : edge e;
3076 27966513 : basic_block bb;
3077 27966513 : tree cond, expanded, backup;
3078 27966513 : int cnt = 0;
3079 :
3080 27966513 : if (TREE_CODE (expr) == INTEGER_CST)
3081 : return expr;
3082 :
3083 2877160 : value_range expr_range (TREE_TYPE (expr));
3084 2877160 : tree val;
3085 2877160 : if (TREE_TYPE (expr) == boolean_type_node
3086 5733186 : && get_range_query (cfun)->range_on_edge (expr_range,
3087 : loop_preheader_edge (loop),
3088 : expr)
3089 5743753 : && expr_range.singleton_p (&val))
3090 84064 : return val;
3091 :
3092 2793096 : backup = expanded = expand_simple_operations (expr);
3093 :
3094 : /* Limit walking the dominators to avoid quadraticness in
3095 : the number of BBs times the number of loops in degenerate
3096 : cases. */
3097 2793096 : for (bb = loop->header;
3098 27219935 : bb != ENTRY_BLOCK_PTR_FOR_FN (cfun)
3099 27219935 : && cnt < param_max_niter_dominators_walk;
3100 24426839 : bb = get_immediate_dominator (CDI_DOMINATORS, bb))
3101 : {
3102 24500190 : if (!single_pred_p (bb))
3103 12344885 : continue;
3104 12155305 : e = single_pred_edge (bb);
3105 :
3106 12155305 : if (!(e->flags & (EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
3107 3478948 : continue;
3108 :
3109 17352714 : gcond *stmt = as_a <gcond *> (*gsi_last_bb (e->src));
3110 8676357 : cond = fold_build2 (gimple_cond_code (stmt),
3111 : boolean_type_node,
3112 : gimple_cond_lhs (stmt),
3113 : gimple_cond_rhs (stmt));
3114 8676357 : if (e->flags & EDGE_FALSE_VALUE)
3115 4886484 : cond = invert_truthvalue (cond);
3116 8676357 : expanded = tree_simplify_using_condition (cond, expanded);
3117 : /* Break if EXPR is simplified to const values. */
3118 8676357 : if (expanded
3119 8676357 : && (integer_zerop (expanded) || integer_nonzerop (expanded)))
3120 73351 : return expanded;
3121 :
3122 8603006 : ++cnt;
3123 : }
3124 :
3125 : /* Return the original expression if no simplification is done. */
3126 2719745 : return operand_equal_p (backup, expanded, 0) ? expr : expanded;
3127 2877160 : }
3128 :
3129 : /* Tries to simplify EXPR using the evolutions of the loop invariants
3130 : in the superloops of LOOP. Returns the simplified expression
3131 : (or EXPR unchanged, if no simplification was possible). */
3132 :
3133 : static tree
3134 6529898 : simplify_using_outer_evolutions (class loop *loop, tree expr)
3135 : {
3136 6529898 : enum tree_code code = TREE_CODE (expr);
3137 6529898 : bool changed;
3138 6529898 : tree e, e0, e1, e2;
3139 :
3140 6529898 : if (is_gimple_min_invariant (expr))
3141 : return expr;
3142 :
3143 1491629 : if (code == TRUTH_OR_EXPR
3144 1491629 : || code == TRUTH_AND_EXPR
3145 1491629 : || code == COND_EXPR)
3146 : {
3147 9049 : changed = false;
3148 :
3149 9049 : e0 = simplify_using_outer_evolutions (loop, TREE_OPERAND (expr, 0));
3150 9049 : if (TREE_OPERAND (expr, 0) != e0)
3151 0 : changed = true;
3152 :
3153 9049 : e1 = simplify_using_outer_evolutions (loop, TREE_OPERAND (expr, 1));
3154 9049 : if (TREE_OPERAND (expr, 1) != e1)
3155 0 : changed = true;
3156 :
3157 9049 : if (code == COND_EXPR)
3158 : {
3159 0 : e2 = simplify_using_outer_evolutions (loop, TREE_OPERAND (expr, 2));
3160 0 : if (TREE_OPERAND (expr, 2) != e2)
3161 : changed = true;
3162 : }
3163 : else
3164 : e2 = NULL_TREE;
3165 :
3166 9049 : if (changed)
3167 : {
3168 0 : if (code == COND_EXPR)
3169 0 : expr = fold_build3 (code, boolean_type_node, e0, e1, e2);
3170 : else
3171 0 : expr = fold_build2 (code, boolean_type_node, e0, e1);
3172 : }
3173 :
3174 9049 : return expr;
3175 : }
3176 :
3177 1482580 : e = instantiate_parameters (loop, expr);
3178 1482580 : if (is_gimple_min_invariant (e))
3179 : return e;
3180 :
3181 : return expr;
3182 : }
3183 :
3184 : /* Returns true if EXIT is the only possible exit from LOOP. */
3185 :
3186 : bool
3187 13282112 : loop_only_exit_p (const class loop *loop, basic_block *body, const_edge exit)
3188 : {
3189 13282112 : gimple_stmt_iterator bsi;
3190 13282112 : unsigned i;
3191 :
3192 13282112 : if (exit != single_exit (loop))
3193 : return false;
3194 :
3195 44690354 : for (i = 0; i < loop->num_nodes; i++)
3196 299894350 : for (bsi = gsi_start_bb (body[i]); !gsi_end_p (bsi); gsi_next (&bsi))
3197 229416342 : if (stmt_can_terminate_bb_p (gsi_stmt (bsi)))
3198 : return false;
3199 :
3200 : return true;
3201 : }
3202 :
3203 : /* Stores description of number of iterations of LOOP derived from
3204 : EXIT (an exit edge of the LOOP) in NITER. Returns true if some useful
3205 : information could be derived (and fields of NITER have meaning described
3206 : in comments at class tree_niter_desc declaration), false otherwise.
3207 : When EVERY_ITERATION is true, only tests that are known to be executed
3208 : every iteration are considered (i.e. only test that alone bounds the loop).
3209 : If AT_STMT is not NULL, this function stores LOOP's condition statement in
3210 : it when returning true. */
3211 :
3212 : bool
3213 24144236 : number_of_iterations_exit_assumptions (class loop *loop, edge exit,
3214 : class tree_niter_desc *niter,
3215 : gcond **at_stmt, bool every_iteration,
3216 : basic_block *body)
3217 : {
3218 24144236 : tree type;
3219 24144236 : tree op0, op1;
3220 24144236 : enum tree_code code;
3221 24144236 : affine_iv iv0, iv1;
3222 24144236 : bool safe;
3223 :
3224 : /* The condition at a fake exit (if it exists) does not control its
3225 : execution. */
3226 24144236 : if (exit->flags & EDGE_FAKE)
3227 : return false;
3228 :
3229 : /* Nothing to analyze if the loop is known to be infinite. */
3230 24143805 : if (loop_constraint_set_p (loop, LOOP_C_INFINITE))
3231 : return false;
3232 :
3233 24143805 : safe = dominated_by_p (CDI_DOMINATORS, loop->latch, exit->src);
3234 :
3235 24143805 : if (every_iteration && !safe)
3236 : return false;
3237 :
3238 23084354 : niter->assumptions = boolean_false_node;
3239 23084354 : niter->control.base = NULL_TREE;
3240 23084354 : niter->control.step = NULL_TREE;
3241 23084354 : niter->control.no_overflow = false;
3242 50749458 : gcond *stmt = safe_dyn_cast <gcond *> (*gsi_last_bb (exit->src));
3243 21123545 : if (!stmt)
3244 : return false;
3245 :
3246 21123545 : if (at_stmt)
3247 20492419 : *at_stmt = stmt;
3248 :
3249 : /* We want the condition for staying inside loop. */
3250 21123545 : code = gimple_cond_code (stmt);
3251 21123545 : if (exit->flags & EDGE_TRUE_VALUE)
3252 7864573 : code = invert_tree_comparison (code, false);
3253 :
3254 21123545 : switch (code)
3255 : {
3256 18014707 : case GT_EXPR:
3257 18014707 : case GE_EXPR:
3258 18014707 : case LT_EXPR:
3259 18014707 : case LE_EXPR:
3260 18014707 : case NE_EXPR:
3261 18014707 : break;
3262 :
3263 3108555 : case EQ_EXPR:
3264 3108555 : return number_of_iterations_cltz (loop, exit, code, niter);
3265 :
3266 : default:
3267 : return false;
3268 : }
3269 :
3270 18014707 : op0 = gimple_cond_lhs (stmt);
3271 18014707 : op1 = gimple_cond_rhs (stmt);
3272 18014707 : type = TREE_TYPE (op0);
3273 :
3274 18014707 : if (!INTEGRAL_NB_TYPE_P (type)
3275 : && !POINTER_TYPE_P (type))
3276 : return false;
3277 :
3278 17250662 : tree iv0_niters = NULL_TREE;
3279 34501324 : if (!simple_iv_with_niters (loop, loop_containing_stmt (stmt),
3280 : op0, &iv0, safe ? &iv0_niters : NULL, false))
3281 3721031 : return number_of_iterations_bitcount (loop, exit, code, niter);
3282 13529631 : tree iv1_niters = NULL_TREE;
3283 27059262 : if (!simple_iv_with_niters (loop, loop_containing_stmt (stmt),
3284 : op1, &iv1, safe ? &iv1_niters : NULL, false))
3285 : return false;
3286 : /* Give up on complicated case. */
3287 12872681 : if (iv0_niters && iv1_niters)
3288 : return false;
3289 :
3290 12872681 : iv0.base = expand_simple_operations (iv0.base);
3291 12872681 : iv1.base = expand_simple_operations (iv1.base);
3292 12872681 : bool body_from_caller = true;
3293 12872681 : if (!body)
3294 : {
3295 7749159 : body = get_loop_body (loop);
3296 7749159 : body_from_caller = false;
3297 : }
3298 12872681 : bool only_exit_p = loop_only_exit_p (loop, body, exit);
3299 12872681 : if (!body_from_caller)
3300 7749159 : free (body);
3301 12872681 : if (!number_of_iterations_cond (loop, type, &iv0, code, &iv1, niter,
3302 : only_exit_p, safe))
3303 : {
3304 : return false;
3305 : }
3306 :
3307 : /* Incorporate additional assumption implied by control iv. */
3308 12733900 : tree iv_niters = iv0_niters ? iv0_niters : iv1_niters;
3309 12733900 : if (iv_niters)
3310 : {
3311 25668 : tree assumption = fold_build2 (LE_EXPR, boolean_type_node, niter->niter,
3312 : fold_convert (TREE_TYPE (niter->niter),
3313 : iv_niters));
3314 :
3315 25668 : if (!integer_nonzerop (assumption))
3316 25477 : niter->assumptions = fold_build2 (TRUTH_AND_EXPR, boolean_type_node,
3317 : niter->assumptions, assumption);
3318 :
3319 : /* Refine upper bound if possible. */
3320 25668 : if (TREE_CODE (iv_niters) == INTEGER_CST
3321 51336 : && niter->max > wi::to_widest (iv_niters))
3322 22388 : niter->max = wi::to_widest (iv_niters);
3323 : }
3324 :
3325 : /* There is no assumptions if the loop is known to be finite. */
3326 12733900 : if (!integer_zerop (niter->assumptions)
3327 12733900 : && loop_constraint_set_p (loop, LOOP_C_FINITE))
3328 12155 : niter->assumptions = boolean_true_node;
3329 :
3330 12733900 : if (optimize >= 3)
3331 : {
3332 2170600 : niter->assumptions = simplify_using_outer_evolutions (loop,
3333 : niter->assumptions);
3334 2170600 : niter->may_be_zero = simplify_using_outer_evolutions (loop,
3335 : niter->may_be_zero);
3336 2170600 : niter->niter = simplify_using_outer_evolutions (loop, niter->niter);
3337 : }
3338 :
3339 12733900 : niter->assumptions
3340 12733900 : = simplify_using_initial_conditions (loop,
3341 : niter->assumptions);
3342 12733900 : niter->may_be_zero
3343 12733900 : = simplify_using_initial_conditions (loop,
3344 : niter->may_be_zero);
3345 :
3346 : /* If NITER has simplified into a constant, update MAX. */
3347 12733900 : if (TREE_CODE (niter->niter) == INTEGER_CST)
3348 7302621 : niter->max = wi::to_widest (niter->niter);
3349 :
3350 12733900 : return (!integer_zerop (niter->assumptions));
3351 : }
3352 :
3353 : /* Like number_of_iterations_exit_assumptions, but return TRUE only if
3354 : the niter information holds unconditionally. */
3355 :
3356 : bool
3357 23420270 : number_of_iterations_exit (class loop *loop, edge exit,
3358 : class tree_niter_desc *niter,
3359 : bool warn, bool every_iteration,
3360 : basic_block *body)
3361 : {
3362 23420270 : gcond *stmt;
3363 23420270 : if (!number_of_iterations_exit_assumptions (loop, exit, niter,
3364 : &stmt, every_iteration, body))
3365 : return false;
3366 :
3367 12385515 : if (integer_nonzerop (niter->assumptions))
3368 : return true;
3369 :
3370 574878 : if (warn && dump_enabled_p ())
3371 5 : dump_printf_loc (MSG_MISSED_OPTIMIZATION, stmt,
3372 : "missed loop optimization: niters analysis ends up "
3373 : "with assumptions.\n");
3374 :
3375 : return false;
3376 : }
3377 :
3378 : /* Try to determine the number of iterations of LOOP. If we succeed,
3379 : expression giving number of iterations is returned and *EXIT is
3380 : set to the edge from that the information is obtained. Otherwise
3381 : chrec_dont_know is returned. */
3382 :
3383 : tree
3384 750885 : find_loop_niter (class loop *loop, edge *exit)
3385 : {
3386 750885 : unsigned i;
3387 750885 : auto_vec<edge> exits = get_loop_exit_edges (loop);
3388 750885 : edge ex;
3389 750885 : tree niter = NULL_TREE, aniter;
3390 750885 : class tree_niter_desc desc;
3391 :
3392 750885 : *exit = NULL;
3393 3253820 : FOR_EACH_VEC_ELT (exits, i, ex)
3394 : {
3395 2502935 : if (!number_of_iterations_exit (loop, ex, &desc, false))
3396 1996946 : continue;
3397 :
3398 505989 : if (integer_nonzerop (desc.may_be_zero))
3399 : {
3400 : /* We exit in the first iteration through this exit.
3401 : We won't find anything better. */
3402 0 : niter = build_int_cst (unsigned_type_node, 0);
3403 0 : *exit = ex;
3404 0 : break;
3405 : }
3406 :
3407 505989 : if (!integer_zerop (desc.may_be_zero))
3408 56450 : continue;
3409 :
3410 449539 : aniter = desc.niter;
3411 :
3412 449539 : if (!niter)
3413 : {
3414 : /* Nothing recorded yet. */
3415 440222 : niter = aniter;
3416 440222 : *exit = ex;
3417 440222 : continue;
3418 : }
3419 :
3420 : /* Prefer constants, the lower the better. */
3421 9317 : if (TREE_CODE (aniter) != INTEGER_CST)
3422 5323 : continue;
3423 :
3424 3994 : if (TREE_CODE (niter) != INTEGER_CST)
3425 : {
3426 960 : niter = aniter;
3427 960 : *exit = ex;
3428 960 : continue;
3429 : }
3430 :
3431 3034 : if (tree_int_cst_lt (aniter, niter))
3432 : {
3433 216 : niter = aniter;
3434 216 : *exit = ex;
3435 216 : continue;
3436 : }
3437 : }
3438 :
3439 750885 : return niter ? niter : chrec_dont_know;
3440 750885 : }
3441 :
3442 : /* Return true if loop is known to have bounded number of iterations. */
3443 :
3444 : bool
3445 2939931 : finite_loop_p (class loop *loop)
3446 : {
3447 2939931 : widest_int nit;
3448 2939931 : int flags;
3449 :
3450 2939931 : if (loop->finite_p)
3451 : {
3452 2179354 : unsigned i;
3453 2179354 : auto_vec<edge> exits = get_loop_exit_edges (loop);
3454 2179354 : edge ex;
3455 :
3456 : /* If the loop has a normal exit, we can assume it will terminate. */
3457 4371363 : FOR_EACH_VEC_ELT (exits, i, ex)
3458 2187225 : if (!(ex->flags & (EDGE_EH | EDGE_ABNORMAL | EDGE_FAKE)))
3459 : {
3460 2174902 : if (dump_file)
3461 172 : fprintf (dump_file, "Assume loop %i to be finite: it has an exit "
3462 : "and -ffinite-loops is on or loop was "
3463 : "previously finite.\n",
3464 : loop->num);
3465 2174902 : return true;
3466 : }
3467 2179354 : }
3468 :
3469 765029 : flags = flags_from_decl_or_type (current_function_decl);
3470 765029 : if ((flags & (ECF_CONST|ECF_PURE)) && !(flags & ECF_LOOPING_CONST_OR_PURE))
3471 : {
3472 1960 : if (dump_file && (dump_flags & TDF_DETAILS))
3473 0 : fprintf (dump_file,
3474 : "Found loop %i to be finite: it is within "
3475 : "pure or const function.\n",
3476 : loop->num);
3477 1960 : loop->finite_p = true;
3478 1960 : return true;
3479 : }
3480 :
3481 763069 : if (loop->any_upper_bound
3482 : /* Loop with no normal exit will not pass max_loop_iterations. */
3483 763069 : || (!loop->finite_p && max_loop_iterations (loop, &nit)))
3484 : {
3485 401714 : if (dump_file && (dump_flags & TDF_DETAILS))
3486 31 : fprintf (dump_file, "Found loop %i to be finite: upper bound found.\n",
3487 : loop->num);
3488 401714 : loop->finite_p = true;
3489 401714 : return true;
3490 : }
3491 :
3492 : return false;
3493 2939931 : }
3494 :
3495 : /*
3496 :
3497 : Analysis of a number of iterations of a loop by a brute-force evaluation.
3498 :
3499 : */
3500 :
3501 : /* Bound on the number of iterations we try to evaluate. */
3502 :
3503 : #define MAX_ITERATIONS_TO_TRACK \
3504 : ((unsigned) param_max_iterations_to_track)
3505 :
3506 : /* Returns the loop phi node of LOOP such that ssa name X is derived from its
3507 : result by a chain of operations such that all but exactly one of their
3508 : operands are constants. */
3509 :
3510 : static gphi *
3511 1919404 : chain_of_csts_start (class loop *loop, tree x)
3512 : {
3513 2297032 : gimple *stmt = SSA_NAME_DEF_STMT (x);
3514 2297032 : tree use;
3515 2297032 : basic_block bb = gimple_bb (stmt);
3516 2297032 : enum tree_code code;
3517 :
3518 2297032 : if (!bb
3519 2297032 : || !flow_bb_inside_loop_p (loop, bb))
3520 527449 : return NULL;
3521 :
3522 1769583 : if (gimple_code (stmt) == GIMPLE_PHI)
3523 : {
3524 709828 : if (bb == loop->header)
3525 646805 : return as_a <gphi *> (stmt);
3526 :
3527 : return NULL;
3528 : }
3529 :
3530 1059755 : if (gimple_code (stmt) != GIMPLE_ASSIGN
3531 2000781 : || gimple_assign_rhs_class (stmt) == GIMPLE_TERNARY_RHS)
3532 : return NULL;
3533 :
3534 940769 : code = gimple_assign_rhs_code (stmt);
3535 940769 : if (gimple_references_memory_p (stmt)
3536 508455 : || TREE_CODE_CLASS (code) == tcc_reference
3537 483430 : || (code == ADDR_EXPR
3538 513 : && !is_gimple_min_invariant (gimple_assign_rhs1 (stmt))))
3539 457852 : return NULL;
3540 :
3541 482917 : use = SINGLE_SSA_TREE_OPERAND (stmt, SSA_OP_USE);
3542 482917 : if (use == NULL_TREE)
3543 : return NULL;
3544 :
3545 : return chain_of_csts_start (loop, use);
3546 : }
3547 :
3548 : /* Determines whether the expression X is derived from a result of a phi node
3549 : in header of LOOP such that
3550 :
3551 : * the derivation of X consists only from operations with constants
3552 : * the initial value of the phi node is constant
3553 : * the value of the phi node in the next iteration can be derived from the
3554 : value in the current iteration by a chain of operations with constants,
3555 : or is also a constant
3556 :
3557 : If such phi node exists, it is returned, otherwise NULL is returned. */
3558 :
3559 : static gphi *
3560 1733605 : get_base_for (class loop *loop, tree x)
3561 : {
3562 1733605 : gphi *phi;
3563 1733605 : tree init, next;
3564 :
3565 1733605 : if (is_gimple_min_invariant (x))
3566 : return NULL;
3567 :
3568 1733605 : phi = chain_of_csts_start (loop, x);
3569 1733605 : if (!phi)
3570 : return NULL;
3571 :
3572 476017 : init = PHI_ARG_DEF_FROM_EDGE (phi, loop_preheader_edge (loop));
3573 476017 : next = PHI_ARG_DEF_FROM_EDGE (phi, loop_latch_edge (loop));
3574 :
3575 476017 : if (!is_gimple_min_invariant (init))
3576 : return NULL;
3577 :
3578 210925 : if (TREE_CODE (next) == SSA_NAME
3579 210925 : && chain_of_csts_start (loop, next) != phi)
3580 : return NULL;
3581 :
3582 : return phi;
3583 : }
3584 :
3585 : /* Given an expression X, then
3586 :
3587 : * if X is NULL_TREE, we return the constant BASE.
3588 : * if X is a constant, we return the constant X.
3589 : * otherwise X is a SSA name, whose value in the considered loop is derived
3590 : by a chain of operations with constant from a result of a phi node in
3591 : the header of the loop. Then we return value of X when the value of the
3592 : result of this phi node is given by the constant BASE. */
3593 :
3594 : static tree
3595 7402967 : get_val_for (tree x, tree base)
3596 : {
3597 7410322 : gimple *stmt;
3598 :
3599 7410322 : gcc_checking_assert (is_gimple_min_invariant (base));
3600 :
3601 7410322 : if (!x)
3602 : return base;
3603 5188630 : else if (is_gimple_min_invariant (x))
3604 : return x;
3605 :
3606 5163898 : stmt = SSA_NAME_DEF_STMT (x);
3607 5163898 : if (gimple_code (stmt) == GIMPLE_PHI)
3608 : return base;
3609 :
3610 2742469 : gcc_checking_assert (is_gimple_assign (stmt));
3611 :
3612 : /* STMT must be either an assignment of a single SSA name or an
3613 : expression involving an SSA name and a constant. Try to fold that
3614 : expression using the value for the SSA name. */
3615 2742469 : if (gimple_assign_ssa_name_copy_p (stmt))
3616 7355 : return get_val_for (gimple_assign_rhs1 (stmt), base);
3617 2735114 : else if (gimple_assign_rhs_class (stmt) == GIMPLE_UNARY_RHS
3618 2735114 : && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME)
3619 285720 : return fold_build1 (gimple_assign_rhs_code (stmt),
3620 : TREE_TYPE (gimple_assign_lhs (stmt)),
3621 : get_val_for (gimple_assign_rhs1 (stmt), base));
3622 2449394 : else if (gimple_assign_rhs_class (stmt) == GIMPLE_BINARY_RHS)
3623 : {
3624 2449394 : tree rhs1 = gimple_assign_rhs1 (stmt);
3625 2449394 : tree rhs2 = gimple_assign_rhs2 (stmt);
3626 2449394 : if (TREE_CODE (rhs1) == SSA_NAME)
3627 2387784 : rhs1 = get_val_for (rhs1, base);
3628 61610 : else if (TREE_CODE (rhs2) == SSA_NAME)
3629 61610 : rhs2 = get_val_for (rhs2, base);
3630 : else
3631 0 : gcc_unreachable ();
3632 2449394 : return fold_build2 (gimple_assign_rhs_code (stmt),
3633 : TREE_TYPE (gimple_assign_lhs (stmt)), rhs1, rhs2);
3634 : }
3635 : else
3636 0 : gcc_unreachable ();
3637 : }
3638 :
3639 :
3640 : /* Tries to count the number of iterations of LOOP till it exits by EXIT
3641 : by brute force -- i.e. by determining the value of the operands of the
3642 : condition at EXIT in first few iterations of the loop (assuming that
3643 : these values are constant) and determining the first one in that the
3644 : condition is not satisfied. Returns the constant giving the number
3645 : of the iterations of LOOP if successful, chrec_dont_know otherwise. */
3646 :
3647 : tree
3648 1688421 : loop_niter_by_eval (class loop *loop, edge exit)
3649 : {
3650 1688421 : tree acnd;
3651 1688421 : tree op[2], val[2], next[2], aval[2];
3652 1688421 : gphi *phi;
3653 1688421 : unsigned i, j;
3654 1688421 : enum tree_code cmp;
3655 :
3656 3376842 : gcond *cond = safe_dyn_cast <gcond *> (*gsi_last_bb (exit->src));
3657 1688421 : if (!cond)
3658 121906 : return chrec_dont_know;
3659 :
3660 1566515 : cmp = gimple_cond_code (cond);
3661 1566515 : if (exit->flags & EDGE_TRUE_VALUE)
3662 565638 : cmp = invert_tree_comparison (cmp, false);
3663 :
3664 1566515 : switch (cmp)
3665 : {
3666 1566490 : case EQ_EXPR:
3667 1566490 : case NE_EXPR:
3668 1566490 : case GT_EXPR:
3669 1566490 : case GE_EXPR:
3670 1566490 : case LT_EXPR:
3671 1566490 : case LE_EXPR:
3672 1566490 : op[0] = gimple_cond_lhs (cond);
3673 1566490 : op[1] = gimple_cond_rhs (cond);
3674 1566490 : break;
3675 :
3676 25 : default:
3677 25 : return chrec_dont_know;
3678 : }
3679 :
3680 1790895 : for (j = 0; j < 2; j++)
3681 : {
3682 1762130 : if (is_gimple_min_invariant (op[j]))
3683 : {
3684 28525 : val[j] = op[j];
3685 28525 : next[j] = NULL_TREE;
3686 28525 : op[j] = NULL_TREE;
3687 : }
3688 : else
3689 : {
3690 1733605 : phi = get_base_for (loop, op[j]);
3691 1733605 : if (!phi)
3692 : {
3693 1537725 : gassign *def;
3694 1537725 : if (j == 0
3695 1370850 : && (cmp == NE_EXPR || cmp == EQ_EXPR)
3696 789289 : && TREE_CODE (op[0]) == SSA_NAME
3697 789289 : && TREE_CODE (op[1]) == INTEGER_CST
3698 508046 : && (def = dyn_cast <gassign *> (SSA_NAME_DEF_STMT (op[0])))
3699 1810229 : && gimple_assign_rhs_code (def) == MEM_REF)
3700 : {
3701 58831 : tree mem = gimple_assign_rhs1 (def);
3702 58831 : affine_iv iv;
3703 58831 : if (TYPE_MODE (TREE_TYPE (mem)) == TYPE_MODE (char_type_node)
3704 22845 : && simple_iv (loop, loop,
3705 22845 : TREE_OPERAND (mem, 0), &iv, false)
3706 16498 : && tree_fits_uhwi_p (TREE_OPERAND (mem, 1))
3707 75329 : && tree_fits_uhwi_p (iv.step))
3708 : {
3709 16498 : tree str, off;
3710 : /* iv.base can be &"Foo" but also (char *)&"Foo" + 1. */
3711 16498 : split_constant_offset (iv.base, &str, &off);
3712 16498 : STRIP_NOPS (str);
3713 16498 : if (TREE_CODE (str) == ADDR_EXPR
3714 3202 : && TREE_CODE (TREE_OPERAND (str, 0)) == STRING_CST
3715 18224 : && tree_fits_uhwi_p (off))
3716 : {
3717 1726 : str = TREE_OPERAND (str, 0);
3718 1726 : unsigned i = 0;
3719 3452 : for (unsigned HOST_WIDE_INT idx
3720 1726 : = (tree_to_uhwi (TREE_OPERAND (mem, 1))
3721 1726 : + tree_to_uhwi (off));
3722 25650 : idx < (unsigned)TREE_STRING_LENGTH (str)
3723 12825 : && i < MAX_ITERATIONS_TO_TRACK;
3724 11099 : idx += tree_to_uhwi (iv.step), ++i)
3725 : {
3726 12031 : int res = compare_tree_int
3727 12031 : (op[1], TREE_STRING_POINTER (str)[idx]);
3728 12031 : if ((cmp == NE_EXPR && res == 0)
3729 11118 : || (cmp == EQ_EXPR && res != 0))
3730 932 : return build_int_cst (unsigned_type_node, i);
3731 : }
3732 : }
3733 : }
3734 : }
3735 1536793 : return chrec_dont_know;
3736 : }
3737 195880 : val[j] = PHI_ARG_DEF_FROM_EDGE (phi, loop_preheader_edge (loop));
3738 195880 : next[j] = PHI_ARG_DEF_FROM_EDGE (phi, loop_latch_edge (loop));
3739 : }
3740 : }
3741 :
3742 1181612 : for (i = 0; i < MAX_ITERATIONS_TO_TRACK; i++)
3743 : {
3744 3542109 : for (j = 0; j < 2; j++)
3745 2361406 : aval[j] = get_val_for (op[j], val[j]);
3746 :
3747 1180703 : acnd = fold_binary (cmp, boolean_type_node, aval[0], aval[1]);
3748 1180703 : if (acnd && integer_zerop (acnd))
3749 : {
3750 27128 : if (dump_file && (dump_flags & TDF_DETAILS))
3751 3 : fprintf (dump_file,
3752 : "Proved that loop %d iterates %d times using brute force.\n",
3753 : loop->num, i);
3754 27128 : return build_int_cst (unsigned_type_node, i);
3755 : }
3756 :
3757 3459319 : for (j = 0; j < 2; j++)
3758 : {
3759 2306447 : aval[j] = val[j];
3760 2306447 : val[j] = get_val_for (next[j], val[j]);
3761 2306447 : if (!is_gimple_min_invariant (val[j]))
3762 703 : return chrec_dont_know;
3763 : }
3764 :
3765 : /* If the next iteration would use the same base values
3766 : as the current one, there is no point looping further,
3767 : all following iterations will be the same as this one. */
3768 1152872 : if (val[0] == aval[0] && val[1] == aval[1])
3769 : break;
3770 : }
3771 :
3772 934 : return chrec_dont_know;
3773 : }
3774 :
3775 : /* Finds the exit of the LOOP by that the loop exits after a constant
3776 : number of iterations and stores the exit edge to *EXIT. The constant
3777 : giving the number of iterations of LOOP is returned. The number of
3778 : iterations is determined using loop_niter_by_eval (i.e. by brute force
3779 : evaluation). If we are unable to find the exit for that loop_niter_by_eval
3780 : determines the number of iterations, chrec_dont_know is returned. */
3781 :
3782 : tree
3783 775745 : find_loop_niter_by_eval (class loop *loop, edge *exit)
3784 : {
3785 775745 : unsigned i;
3786 775745 : auto_vec<edge> exits = get_loop_exit_edges (loop);
3787 775745 : edge ex;
3788 775745 : tree niter = NULL_TREE, aniter;
3789 :
3790 775745 : *exit = NULL;
3791 :
3792 : /* Loops with multiple exits are expensive to handle and less important. */
3793 775745 : if (!flag_expensive_optimizations
3794 796159 : && exits.length () > 1)
3795 4305 : return chrec_dont_know;
3796 :
3797 2316543 : FOR_EACH_VEC_ELT (exits, i, ex)
3798 : {
3799 1545103 : if (!just_once_each_iteration_p (loop, ex->src))
3800 412394 : continue;
3801 :
3802 1132709 : aniter = loop_niter_by_eval (loop, ex);
3803 1132709 : if (chrec_contains_undetermined (aniter))
3804 1117509 : continue;
3805 :
3806 15243 : if (niter
3807 15200 : && !tree_int_cst_lt (aniter, niter))
3808 43 : continue;
3809 :
3810 15157 : niter = aniter;
3811 15157 : *exit = ex;
3812 : }
3813 :
3814 771440 : return niter ? niter : chrec_dont_know;
3815 775745 : }
3816 :
3817 : /*
3818 :
3819 : Analysis of upper bounds on number of iterations of a loop.
3820 :
3821 : */
3822 :
3823 : static widest_int derive_constant_upper_bound_ops (tree, tree,
3824 : enum tree_code, tree);
3825 :
3826 : /* Returns a constant upper bound on the value of the right-hand side of
3827 : an assignment statement STMT. */
3828 :
3829 : static widest_int
3830 279 : derive_constant_upper_bound_assign (gimple *stmt)
3831 : {
3832 279 : enum tree_code code = gimple_assign_rhs_code (stmt);
3833 279 : tree op0 = gimple_assign_rhs1 (stmt);
3834 279 : tree op1 = gimple_assign_rhs2 (stmt);
3835 :
3836 279 : return derive_constant_upper_bound_ops (TREE_TYPE (gimple_assign_lhs (stmt)),
3837 279 : op0, code, op1);
3838 : }
3839 :
3840 : /* Returns a constant upper bound on the value of expression VAL. VAL
3841 : is considered to be unsigned. If its type is signed, its value must
3842 : be nonnegative. */
3843 :
3844 : static widest_int
3845 11177249 : derive_constant_upper_bound (tree val)
3846 : {
3847 11177249 : enum tree_code code;
3848 11177249 : tree op0, op1, op2;
3849 :
3850 11177249 : extract_ops_from_tree (val, &code, &op0, &op1, &op2);
3851 11177249 : return derive_constant_upper_bound_ops (TREE_TYPE (val), op0, code, op1);
3852 : }
3853 :
3854 : /* Returns a constant upper bound on the value of expression OP0 CODE OP1,
3855 : whose type is TYPE. The expression is considered to be unsigned. If
3856 : its type is signed, its value must be nonnegative. */
3857 :
3858 : static widest_int
3859 11177528 : derive_constant_upper_bound_ops (tree type, tree op0,
3860 : enum tree_code code, tree op1)
3861 : {
3862 11177528 : tree subtype, maxt;
3863 11177528 : widest_int bnd, max, cst;
3864 11177528 : gimple *stmt;
3865 :
3866 11177528 : if (INTEGRAL_TYPE_P (type))
3867 11177528 : maxt = TYPE_MAX_VALUE (type);
3868 : else
3869 0 : maxt = upper_bound_in_type (type, type);
3870 :
3871 11177528 : max = wi::to_widest (maxt);
3872 :
3873 11177528 : switch (code)
3874 : {
3875 11103921 : case INTEGER_CST:
3876 11103921 : return wi::to_widest (op0);
3877 :
3878 1053 : CASE_CONVERT:
3879 1053 : subtype = TREE_TYPE (op0);
3880 1053 : if (!TYPE_UNSIGNED (subtype)
3881 : /* If TYPE is also signed, the fact that VAL is nonnegative implies
3882 : that OP0 is nonnegative. */
3883 774 : && TYPE_UNSIGNED (type)
3884 1827 : && !tree_expr_nonnegative_p (op0))
3885 : {
3886 : /* If we cannot prove that the casted expression is nonnegative,
3887 : we cannot establish more useful upper bound than the precision
3888 : of the type gives us. */
3889 751 : return max;
3890 : }
3891 :
3892 : /* We now know that op0 is an nonnegative value. Try deriving an upper
3893 : bound for it. */
3894 302 : bnd = derive_constant_upper_bound (op0);
3895 :
3896 : /* If the bound does not fit in TYPE, max. value of TYPE could be
3897 : attained. */
3898 302 : if (wi::ltu_p (max, bnd))
3899 0 : return max;
3900 :
3901 302 : return bnd;
3902 :
3903 42251 : case PLUS_EXPR:
3904 42251 : case POINTER_PLUS_EXPR:
3905 42251 : case MINUS_EXPR:
3906 42251 : if (TREE_CODE (op1) != INTEGER_CST
3907 42251 : || !tree_expr_nonnegative_p (op0))
3908 41820 : return max;
3909 :
3910 : /* Canonicalize to OP0 - CST. Consider CST to be signed, in order to
3911 : choose the most logical way how to treat this constant regardless
3912 : of the signedness of the type. */
3913 431 : cst = wi::sext (wi::to_widest (op1), TYPE_PRECISION (type));
3914 431 : if (code != MINUS_EXPR)
3915 431 : cst = -cst;
3916 :
3917 431 : bnd = derive_constant_upper_bound (op0);
3918 :
3919 431 : if (wi::neg_p (cst))
3920 : {
3921 29 : cst = -cst;
3922 : /* Avoid CST == 0x80000... */
3923 29 : if (wi::neg_p (cst))
3924 0 : return max;
3925 :
3926 : /* OP0 + CST. We need to check that
3927 : BND <= MAX (type) - CST. */
3928 :
3929 29 : widest_int mmax = max - cst;
3930 29 : if (wi::leu_p (bnd, mmax))
3931 0 : return max;
3932 :
3933 29 : return bnd + cst;
3934 29 : }
3935 : else
3936 : {
3937 : /* OP0 - CST, where CST >= 0.
3938 :
3939 : If TYPE is signed, we have already verified that OP0 >= 0, and we
3940 : know that the result is nonnegative. This implies that
3941 : VAL <= BND - CST.
3942 :
3943 : If TYPE is unsigned, we must additionally know that OP0 >= CST,
3944 : otherwise the operation underflows.
3945 : */
3946 :
3947 : /* This should only happen if the type is unsigned; however, for
3948 : buggy programs that use overflowing signed arithmetics even with
3949 : -fno-wrapv, this condition may also be true for signed values. */
3950 402 : if (wi::ltu_p (bnd, cst))
3951 0 : return max;
3952 :
3953 402 : if (TYPE_UNSIGNED (type))
3954 : {
3955 402 : tree tem = fold_binary (GE_EXPR, boolean_type_node, op0,
3956 : wide_int_to_tree (type, cst));
3957 402 : if (!tem || integer_nonzerop (tem))
3958 50 : return max;
3959 : }
3960 :
3961 352 : bnd -= cst;
3962 : }
3963 :
3964 352 : return bnd;
3965 :
3966 0 : case FLOOR_DIV_EXPR:
3967 0 : case EXACT_DIV_EXPR:
3968 0 : if (TREE_CODE (op1) != INTEGER_CST
3969 0 : || tree_int_cst_sign_bit (op1))
3970 0 : return max;
3971 :
3972 0 : bnd = derive_constant_upper_bound (op0);
3973 0 : return wi::udiv_floor (bnd, wi::to_widest (op1));
3974 :
3975 7 : case BIT_AND_EXPR:
3976 7 : if (TREE_CODE (op1) != INTEGER_CST
3977 7 : || tree_int_cst_sign_bit (op1))
3978 0 : return max;
3979 7 : return wi::to_widest (op1);
3980 :
3981 473 : case SSA_NAME:
3982 473 : stmt = SSA_NAME_DEF_STMT (op0);
3983 473 : if (gimple_code (stmt) != GIMPLE_ASSIGN
3984 473 : || gimple_assign_lhs (stmt) != op0)
3985 194 : return max;
3986 279 : return derive_constant_upper_bound_assign (stmt);
3987 :
3988 29823 : default:
3989 29823 : return max;
3990 : }
3991 11177541 : }
3992 :
3993 : /* Emit a -Waggressive-loop-optimizations warning if needed. */
3994 :
3995 : static void
3996 10226750 : do_warn_aggressive_loop_optimizations (class loop *loop,
3997 : widest_int i_bound, gimple *stmt)
3998 : {
3999 : /* Don't warn if the loop doesn't have known constant bound. */
4000 10226750 : if (!loop->nb_iterations
4001 10226750 : || TREE_CODE (loop->nb_iterations) != INTEGER_CST
4002 4784154 : || !warn_aggressive_loop_optimizations
4003 : /* To avoid warning multiple times for the same loop,
4004 : only start warning when we preserve loops. */
4005 4783987 : || (cfun->curr_properties & PROP_loops) == 0
4006 : /* Only warn once per loop. */
4007 4783987 : || loop->warned_aggressive_loop_optimizations
4008 : /* Only warn if undefined behavior gives us lower estimate than the
4009 : known constant bound. */
4010 4783219 : || wi::cmpu (i_bound, wi::to_widest (loop->nb_iterations)) >= 0
4011 : /* And undefined behavior happens unconditionally. */
4012 10226805 : || !dominated_by_p (CDI_DOMINATORS, loop->latch, gimple_bb (stmt)))
4013 10226695 : return;
4014 :
4015 55 : edge e = single_exit (loop);
4016 55 : if (e == NULL)
4017 : return;
4018 :
4019 55 : gimple *estmt = last_nondebug_stmt (e->src);
4020 55 : char buf[WIDE_INT_PRINT_BUFFER_SIZE], *p;
4021 55 : unsigned len;
4022 55 : if (print_dec_buf_size (i_bound, TYPE_SIGN (TREE_TYPE (loop->nb_iterations)),
4023 : &len))
4024 0 : p = XALLOCAVEC (char, len);
4025 : else
4026 : p = buf;
4027 55 : print_dec (i_bound, p, TYPE_SIGN (TREE_TYPE (loop->nb_iterations)));
4028 55 : auto_diagnostic_group d;
4029 55 : if (warning_at (gimple_location (stmt), OPT_Waggressive_loop_optimizations,
4030 : "iteration %s invokes undefined behavior", p))
4031 9 : inform (gimple_location (estmt), "within this loop");
4032 55 : loop->warned_aggressive_loop_optimizations = true;
4033 55 : }
4034 :
4035 : /* Records that AT_STMT is executed at most BOUND + 1 times in LOOP. IS_EXIT
4036 : is true if the loop is exited immediately after STMT, and this exit
4037 : is taken at last when the STMT is executed BOUND + 1 times.
4038 : REALISTIC is true if BOUND is expected to be close to the real number
4039 : of iterations. UPPER is true if we are sure the loop iterates at most
4040 : BOUND times. I_BOUND is a widest_int upper estimate on BOUND. */
4041 :
4042 : static void
4043 15908971 : record_estimate (class loop *loop, tree bound, const widest_int &i_bound,
4044 : gimple *at_stmt, bool is_exit, bool realistic, bool upper)
4045 : {
4046 15908971 : widest_int delta;
4047 :
4048 15908971 : if (dump_file && (dump_flags & TDF_DETAILS))
4049 : {
4050 125027 : fprintf (dump_file, "Statement %s", is_exit ? "(exit)" : "");
4051 69351 : print_gimple_stmt (dump_file, at_stmt, 0, TDF_SLIM);
4052 70040 : fprintf (dump_file, " is %sexecuted at most ",
4053 : upper ? "" : "probably ");
4054 69351 : print_generic_expr (dump_file, bound, TDF_SLIM);
4055 69351 : fprintf (dump_file, " (bounded by ");
4056 69351 : print_decu (i_bound, dump_file);
4057 69351 : fprintf (dump_file, ") + 1 times in loop %d.\n", loop->num);
4058 : }
4059 :
4060 : /* If the I_BOUND is just an estimate of BOUND, it rarely is close to the
4061 : real number of iterations. */
4062 15908971 : if (TREE_CODE (bound) != INTEGER_CST)
4063 : realistic = false;
4064 : else
4065 14045002 : gcc_checking_assert (i_bound == wi::to_widest (bound));
4066 :
4067 15908971 : if (wi::min_precision (i_bound, SIGNED) > bound_wide_int ().get_precision ())
4068 : return;
4069 :
4070 : /* If we have a guaranteed upper bound, record it in the appropriate
4071 : list, unless this is an !is_exit bound (i.e. undefined behavior in
4072 : at_stmt) in a loop with known constant number of iterations. */
4073 15908944 : if (upper
4074 15377576 : && (is_exit
4075 10645135 : || loop->nb_iterations == NULL_TREE
4076 10645135 : || TREE_CODE (loop->nb_iterations) != INTEGER_CST))
4077 : {
4078 10395242 : class nb_iter_bound *elt = ggc_alloc<nb_iter_bound> ();
4079 :
4080 10395242 : elt->bound = bound_wide_int::from (i_bound, SIGNED);
4081 10395242 : elt->stmt = at_stmt;
4082 10395242 : elt->is_exit = is_exit;
4083 10395242 : elt->next = loop->bounds;
4084 10395242 : loop->bounds = elt;
4085 : }
4086 :
4087 : /* If statement is executed on every path to the loop latch, we can directly
4088 : infer the upper bound on the # of iterations of the loop. */
4089 15908944 : if (!dominated_by_p (CDI_DOMINATORS, loop->latch, gimple_bb (at_stmt)))
4090 487566 : upper = false;
4091 :
4092 : /* Update the number of iteration estimates according to the bound.
4093 : If at_stmt is an exit then the loop latch is executed at most BOUND times,
4094 : otherwise it can be executed BOUND + 1 times. We will lower the estimate
4095 : later if such statement must be executed on last iteration */
4096 15908944 : if (is_exit)
4097 4732443 : delta = 0;
4098 : else
4099 11176501 : delta = 1;
4100 15908944 : widest_int new_i_bound = i_bound + delta;
4101 :
4102 : /* If an overflow occurred, ignore the result. */
4103 15908944 : if (wi::ltu_p (new_i_bound, delta))
4104 0 : return;
4105 :
4106 15908944 : if (upper && !is_exit)
4107 10226750 : do_warn_aggressive_loop_optimizations (loop, new_i_bound, at_stmt);
4108 15908944 : record_niter_bound (loop, new_i_bound, realistic, upper);
4109 15908971 : }
4110 :
4111 : /* Records the control iv analyzed in NITER for LOOP if the iv is valid
4112 : and doesn't overflow. */
4113 :
4114 : static void
4115 4732455 : record_control_iv (class loop *loop, class tree_niter_desc *niter)
4116 : {
4117 4732455 : struct control_iv *iv;
4118 :
4119 4732455 : if (!niter->control.base || !niter->control.step)
4120 : return;
4121 :
4122 4694382 : if (!integer_onep (niter->assumptions) || !niter->control.no_overflow)
4123 : return;
4124 :
4125 4552456 : iv = ggc_alloc<control_iv> ();
4126 4552456 : iv->base = niter->control.base;
4127 4552456 : iv->step = niter->control.step;
4128 4552456 : iv->next = loop->control_ivs;
4129 4552456 : loop->control_ivs = iv;
4130 :
4131 4552456 : return;
4132 : }
4133 :
4134 : /* This function returns TRUE if below conditions are satisfied:
4135 : 1) VAR is SSA variable.
4136 : 2) VAR is an IV:{base, step} in its defining loop.
4137 : 3) IV doesn't overflow.
4138 : 4) Both base and step are integer constants.
4139 : 5) Base is the MIN/MAX value depends on IS_MIN.
4140 : Store value of base to INIT correspondingly. */
4141 :
4142 : static bool
4143 122726 : get_cst_init_from_scev (tree var, wide_int *init, bool is_min)
4144 : {
4145 122726 : if (TREE_CODE (var) != SSA_NAME)
4146 : return false;
4147 :
4148 122726 : gimple *def_stmt = SSA_NAME_DEF_STMT (var);
4149 228448 : class loop *loop = loop_containing_stmt (def_stmt);
4150 :
4151 110444 : if (loop == NULL)
4152 : return false;
4153 :
4154 110444 : affine_iv iv;
4155 110444 : if (!simple_iv (loop, loop, var, &iv, false))
4156 : return false;
4157 :
4158 5945 : if (!iv.no_overflow)
4159 : return false;
4160 :
4161 5899 : if (TREE_CODE (iv.base) != INTEGER_CST || TREE_CODE (iv.step) != INTEGER_CST)
4162 : return false;
4163 :
4164 4947 : if (is_min == tree_int_cst_sign_bit (iv.step))
4165 : return false;
4166 :
4167 4722 : *init = wi::to_wide (iv.base);
4168 4722 : return true;
4169 : }
4170 :
4171 : /* Record the estimate on number of iterations of LOOP based on the fact that
4172 : the induction variable BASE + STEP * i evaluated in STMT does not wrap and
4173 : its values belong to the range <LOW, HIGH>. REALISTIC is true if the
4174 : estimated number of iterations is expected to be close to the real one.
4175 : UPPER is true if we are sure the induction variable does not wrap. */
4176 :
4177 : static void
4178 11176514 : record_nonwrapping_iv (class loop *loop, tree base, tree step, gimple *stmt,
4179 : tree low, tree high, bool realistic, bool upper)
4180 : {
4181 11176514 : tree niter_bound, extreme, delta;
4182 11176514 : tree type = TREE_TYPE (base), unsigned_type;
4183 11176514 : tree orig_base = base;
4184 :
4185 11176514 : if (TREE_CODE (step) != INTEGER_CST || integer_zerop (step))
4186 0 : return;
4187 :
4188 11176514 : if (dump_file && (dump_flags & TDF_DETAILS))
4189 : {
4190 55676 : fprintf (dump_file, "Induction variable (");
4191 55676 : print_generic_expr (dump_file, TREE_TYPE (base), TDF_SLIM);
4192 55676 : fprintf (dump_file, ") ");
4193 55676 : print_generic_expr (dump_file, base, TDF_SLIM);
4194 55676 : fprintf (dump_file, " + ");
4195 55676 : print_generic_expr (dump_file, step, TDF_SLIM);
4196 55676 : fprintf (dump_file, " * iteration does not wrap in statement ");
4197 55676 : print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
4198 55676 : fprintf (dump_file, " in loop %d.\n", loop->num);
4199 : }
4200 :
4201 11176514 : unsigned_type = unsigned_type_for (type);
4202 11176514 : base = fold_convert (unsigned_type, base);
4203 11176514 : step = fold_convert (unsigned_type, step);
4204 :
4205 11176514 : if (tree_int_cst_sign_bit (step))
4206 : {
4207 344406 : wide_int max;
4208 344406 : value_range base_range (TREE_TYPE (orig_base));
4209 688812 : if (get_range_query (cfun)->range_of_expr (base_range, orig_base)
4210 344406 : && !base_range.undefined_p ())
4211 344327 : max = wi::to_wide (base_range.ubound ());
4212 344406 : extreme = fold_convert (unsigned_type, low);
4213 344406 : if (TREE_CODE (orig_base) == SSA_NAME
4214 20066 : && TREE_CODE (high) == INTEGER_CST
4215 20066 : && INTEGRAL_TYPE_P (TREE_TYPE (orig_base))
4216 19992 : && ((!base_range.varying_p ()
4217 6793 : && !base_range.undefined_p ())
4218 13278 : || get_cst_init_from_scev (orig_base, &max, false))
4219 351120 : && wi::gts_p (wi::to_wide (high), max))
4220 1936 : base = wide_int_to_tree (unsigned_type, max);
4221 342470 : else if (TREE_CODE (base) != INTEGER_CST
4222 550918 : && dominated_by_p (CDI_DOMINATORS,
4223 208448 : loop->latch, gimple_bb (stmt)))
4224 206792 : base = fold_convert (unsigned_type, high);
4225 344406 : delta = fold_build2 (MINUS_EXPR, unsigned_type, base, extreme);
4226 344406 : step = fold_build1 (NEGATE_EXPR, unsigned_type, step);
4227 344407 : }
4228 : else
4229 : {
4230 10832108 : wide_int min;
4231 10832108 : value_range base_range (TREE_TYPE (orig_base));
4232 21664216 : if (get_range_query (cfun)->range_of_expr (base_range, orig_base)
4233 10832108 : && !base_range.undefined_p ())
4234 10829830 : min = wi::to_wide (base_range.lbound ());
4235 10832108 : extreme = fold_convert (unsigned_type, high);
4236 10832108 : if (TREE_CODE (orig_base) == SSA_NAME
4237 868071 : && TREE_CODE (low) == INTEGER_CST
4238 868071 : && INTEGRAL_TYPE_P (TREE_TYPE (orig_base))
4239 268762 : && ((!base_range.varying_p ()
4240 161309 : && !base_range.undefined_p ())
4241 109448 : || get_cst_init_from_scev (orig_base, &min, true))
4242 10996144 : && wi::gts_p (min, wi::to_wide (low)))
4243 12870 : base = wide_int_to_tree (unsigned_type, min);
4244 10819238 : else if (TREE_CODE (base) != INTEGER_CST
4245 14225882 : && dominated_by_p (CDI_DOMINATORS,
4246 3406644 : loop->latch, gimple_bb (stmt)))
4247 3335705 : base = fold_convert (unsigned_type, low);
4248 10832108 : delta = fold_build2 (MINUS_EXPR, unsigned_type, extreme, base);
4249 10832120 : }
4250 :
4251 : /* STMT is executed at most NITER_BOUND + 1 times, since otherwise the value
4252 : would get out of the range. */
4253 11176514 : niter_bound = fold_build2 (FLOOR_DIV_EXPR, unsigned_type, delta, step);
4254 11176514 : widest_int max = derive_constant_upper_bound (niter_bound);
4255 11176514 : record_estimate (loop, niter_bound, max, stmt, false, realistic, upper);
4256 11176514 : }
4257 :
4258 : /* Determine information about number of iterations a LOOP from the index
4259 : IDX of a data reference accessed in STMT. RELIABLE is true if STMT is
4260 : guaranteed to be executed in every iteration of LOOP. Callback for
4261 : for_each_index. */
4262 :
4263 : struct ilb_data
4264 : {
4265 : class loop *loop;
4266 : gimple *stmt;
4267 : };
4268 :
4269 : static bool
4270 35206212 : idx_infer_loop_bounds (tree base, tree *idx, void *dta)
4271 : {
4272 35206212 : struct ilb_data *data = (struct ilb_data *) dta;
4273 35206212 : tree ev, init, step;
4274 35206212 : tree low, high, type, next;
4275 35206212 : bool sign, upper = true, has_flexible_size = false;
4276 35206212 : class loop *loop = data->loop;
4277 :
4278 35206212 : if (TREE_CODE (base) != ARRAY_REF)
4279 : return true;
4280 :
4281 : /* For arrays that might have flexible sizes, it is not guaranteed that they
4282 : do not really extend over their declared size. */
4283 9470582 : if (array_ref_flexible_size_p (base))
4284 : {
4285 2278341 : has_flexible_size = true;
4286 2278341 : upper = false;
4287 : }
4288 :
4289 9470582 : class loop *dloop = loop_containing_stmt (data->stmt);
4290 9470582 : if (!dloop)
4291 : return true;
4292 :
4293 9470582 : ev = analyze_scalar_evolution (dloop, *idx);
4294 9470582 : ev = instantiate_parameters (loop, ev);
4295 9470582 : init = initial_condition (ev);
4296 9470582 : step = evolution_part_in_loop_num (ev, loop->num);
4297 :
4298 9470582 : if (!init
4299 9470582 : || !step
4300 5622218 : || TREE_CODE (step) != INTEGER_CST
4301 4310080 : || integer_zerop (step)
4302 4310080 : || tree_contains_chrecs (init, NULL)
4303 13780662 : || chrec_contains_symbols_defined_in_loop (init, loop->num))
4304 5160502 : return true;
4305 :
4306 4310080 : low = array_ref_low_bound (base);
4307 4310080 : high = array_ref_up_bound (base);
4308 :
4309 : /* The case of nonconstant bounds could be handled, but it would be
4310 : complicated. */
4311 4310080 : if (TREE_CODE (low) != INTEGER_CST
4312 4310080 : || !high
4313 3584083 : || TREE_CODE (high) != INTEGER_CST)
4314 : return true;
4315 3380818 : sign = tree_int_cst_sign_bit (step);
4316 3380818 : type = TREE_TYPE (step);
4317 :
4318 : /* The array that might have flexible size most likely extends
4319 : beyond its bounds. */
4320 3380818 : if (has_flexible_size
4321 3380818 : && operand_equal_p (low, high, 0))
4322 : return true;
4323 :
4324 : /* In case the relevant bound of the array does not fit in type, or
4325 : it does, but bound + step (in type) still belongs into the range of the
4326 : array, the index may wrap and still stay within the range of the array
4327 : (consider e.g. if the array is indexed by the full range of
4328 : unsigned char).
4329 :
4330 : To make things simpler, we require both bounds to fit into type, although
4331 : there are cases where this would not be strictly necessary. */
4332 3361808 : if (!int_fits_type_p (high, type)
4333 3361776 : || !int_fits_type_p (low, type))
4334 : return true;
4335 3361776 : low = fold_convert (type, low);
4336 3361776 : high = fold_convert (type, high);
4337 :
4338 3361776 : if (sign)
4339 59527 : next = fold_binary (PLUS_EXPR, type, low, step);
4340 : else
4341 3302249 : next = fold_binary (PLUS_EXPR, type, high, step);
4342 :
4343 3361776 : if (tree_int_cst_compare (low, next) <= 0
4344 3361776 : && tree_int_cst_compare (next, high) <= 0)
4345 : return true;
4346 :
4347 : /* If access is not executed on every iteration, we must ensure that overflow
4348 : may not make the access valid later. */
4349 3361776 : if (!dominated_by_p (CDI_DOMINATORS, loop->latch, gimple_bb (data->stmt)))
4350 : {
4351 478833 : if (scev_probably_wraps_p (NULL_TREE,
4352 478833 : initial_condition_in_loop_num (ev, loop->num),
4353 : step, data->stmt, loop, true))
4354 3361776 : upper = false;
4355 : }
4356 : else
4357 2882943 : record_nonwrapping_chrec (ev);
4358 :
4359 3361776 : record_nonwrapping_iv (loop, init, step, data->stmt, low, high, false, upper);
4360 3361776 : return true;
4361 : }
4362 :
4363 : /* Determine information about number of iterations a LOOP from the bounds
4364 : of arrays in the data reference REF accessed in STMT. RELIABLE is true if
4365 : STMT is guaranteed to be executed in every iteration of LOOP.*/
4366 :
4367 : static void
4368 35923900 : infer_loop_bounds_from_ref (class loop *loop, gimple *stmt, tree ref)
4369 : {
4370 35923900 : struct ilb_data data;
4371 :
4372 35923900 : data.loop = loop;
4373 35923900 : data.stmt = stmt;
4374 0 : for_each_index (&ref, idx_infer_loop_bounds, &data);
4375 0 : }
4376 :
4377 : /* Determine information about number of iterations of a LOOP from the way
4378 : arrays are used in STMT. RELIABLE is true if STMT is guaranteed to be
4379 : executed in every iteration of LOOP. */
4380 :
4381 : static void
4382 257020215 : infer_loop_bounds_from_array (class loop *loop, gimple *stmt)
4383 : {
4384 257020215 : if (is_gimple_assign (stmt))
4385 : {
4386 103476338 : tree op0 = gimple_assign_lhs (stmt);
4387 103476338 : tree op1 = gimple_assign_rhs1 (stmt);
4388 :
4389 : /* For each memory access, analyze its access function
4390 : and record a bound on the loop iteration domain. */
4391 103476338 : if (REFERENCE_CLASS_P (op0))
4392 14034204 : infer_loop_bounds_from_ref (loop, stmt, op0);
4393 :
4394 103476338 : if (REFERENCE_CLASS_P (op1))
4395 21717052 : infer_loop_bounds_from_ref (loop, stmt, op1);
4396 : }
4397 153543877 : else if (is_gimple_call (stmt))
4398 : {
4399 7245983 : tree arg, lhs;
4400 7245983 : unsigned i, n = gimple_call_num_args (stmt);
4401 :
4402 7245983 : lhs = gimple_call_lhs (stmt);
4403 7245983 : if (lhs && REFERENCE_CLASS_P (lhs))
4404 5048 : infer_loop_bounds_from_ref (loop, stmt, lhs);
4405 :
4406 23473555 : for (i = 0; i < n; i++)
4407 : {
4408 16227572 : arg = gimple_call_arg (stmt, i);
4409 16227572 : if (REFERENCE_CLASS_P (arg))
4410 167596 : infer_loop_bounds_from_ref (loop, stmt, arg);
4411 : }
4412 : }
4413 257020215 : }
4414 :
4415 : /* Determine information about number of iterations of a LOOP from the fact
4416 : that pointer arithmetics in STMT does not overflow. */
4417 :
4418 : static void
4419 126636479 : infer_loop_bounds_from_pointer_arith (class loop *loop, gimple *stmt)
4420 : {
4421 126636479 : tree def, base, step, scev, type, low, high;
4422 126636479 : tree var, ptr;
4423 :
4424 126636479 : if (!is_gimple_assign (stmt)
4425 126636479 : || gimple_assign_rhs_code (stmt) != POINTER_PLUS_EXPR)
4426 : return;
4427 :
4428 4556470 : def = gimple_assign_lhs (stmt);
4429 4556470 : if (TREE_CODE (def) != SSA_NAME)
4430 : return;
4431 :
4432 4556470 : type = TREE_TYPE (def);
4433 4556470 : if (!nowrap_type_p (type))
4434 : return;
4435 :
4436 4556470 : ptr = gimple_assign_rhs1 (stmt);
4437 4556470 : if (!expr_invariant_in_loop_p (loop, ptr))
4438 : return;
4439 :
4440 2527849 : var = gimple_assign_rhs2 (stmt);
4441 2527849 : if (TYPE_PRECISION (type) != TYPE_PRECISION (TREE_TYPE (var)))
4442 : return;
4443 :
4444 2527849 : class loop *uloop = loop_containing_stmt (stmt);
4445 2527849 : scev = instantiate_parameters (loop, analyze_scalar_evolution (uloop, def));
4446 2527849 : if (chrec_contains_undetermined (scev))
4447 : return;
4448 :
4449 2123510 : base = initial_condition_in_loop_num (scev, loop->num);
4450 2123510 : step = evolution_part_in_loop_num (scev, loop->num);
4451 :
4452 2123510 : if (!base || !step
4453 2075078 : || TREE_CODE (step) != INTEGER_CST
4454 1875343 : || tree_contains_chrecs (base, NULL)
4455 3998853 : || chrec_contains_symbols_defined_in_loop (base, loop->num))
4456 248167 : return;
4457 :
4458 1875343 : low = lower_bound_in_type (type, type);
4459 1875343 : high = upper_bound_in_type (type, type);
4460 :
4461 : /* In C, pointer arithmetic p + 1 cannot use a NULL pointer, and p - 1 cannot
4462 : produce a NULL pointer. The contrary would mean NULL points to an object,
4463 : while NULL is supposed to compare unequal with the address of all objects.
4464 : Furthermore, p + 1 cannot produce a NULL pointer and p - 1 cannot use a
4465 : NULL pointer since that would mean wrapping, which we assume here not to
4466 : happen. So, we can exclude NULL from the valid range of pointer
4467 : arithmetic. */
4468 1875343 : if (flag_delete_null_pointer_checks && int_cst_value (low) == 0)
4469 1875343 : low = build_int_cstu (TREE_TYPE (low), TYPE_ALIGN_UNIT (TREE_TYPE (type)));
4470 :
4471 1875343 : record_nonwrapping_chrec (scev);
4472 1875343 : record_nonwrapping_iv (loop, base, step, stmt, low, high, false, true);
4473 : }
4474 :
4475 : /* Determine information about number of iterations of a LOOP from the fact
4476 : that signed arithmetics in STMT does not overflow. */
4477 :
4478 : static void
4479 126636479 : infer_loop_bounds_from_signedness (class loop *loop, gimple *stmt)
4480 : {
4481 126636479 : tree def, base, step, scev, type, low, high;
4482 :
4483 126636479 : if (gimple_code (stmt) != GIMPLE_ASSIGN)
4484 120697084 : return;
4485 :
4486 52042555 : def = gimple_assign_lhs (stmt);
4487 :
4488 52042555 : if (TREE_CODE (def) != SSA_NAME)
4489 : return;
4490 :
4491 44494724 : type = TREE_TYPE (def);
4492 44494724 : if (!INTEGRAL_TYPE_P (type)
4493 44494724 : || !TYPE_OVERFLOW_UNDEFINED (type))
4494 : return;
4495 :
4496 14980153 : scev = instantiate_parameters (loop, analyze_scalar_evolution (loop, def));
4497 14980153 : if (chrec_contains_undetermined (scev))
4498 : return;
4499 :
4500 7403836 : base = initial_condition_in_loop_num (scev, loop->num);
4501 7403836 : step = evolution_part_in_loop_num (scev, loop->num);
4502 :
4503 7403836 : if (!base || !step
4504 6609203 : || TREE_CODE (step) != INTEGER_CST
4505 5939395 : || tree_contains_chrecs (base, NULL)
4506 13343231 : || chrec_contains_symbols_defined_in_loop (base, loop->num))
4507 1464441 : return;
4508 :
4509 5939395 : low = lower_bound_in_type (type, type);
4510 5939395 : high = upper_bound_in_type (type, type);
4511 5939395 : int_range_max r (TREE_TYPE (def));
4512 11878790 : get_range_query (cfun)->range_of_expr (r, def);
4513 5939395 : if (!r.varying_p () && !r.undefined_p ())
4514 : {
4515 5431220 : low = wide_int_to_tree (type, r.lower_bound ());
4516 5431232 : high = wide_int_to_tree (type, r.upper_bound ());
4517 : }
4518 :
4519 5939395 : record_nonwrapping_chrec (scev);
4520 5939395 : record_nonwrapping_iv (loop, base, step, stmt, low, high, false, true);
4521 5939395 : }
4522 :
4523 : /* The following analyzers are extracting information on the bounds
4524 : of LOOP from the following undefined behaviors:
4525 :
4526 : - data references should not access elements over the statically
4527 : allocated size,
4528 :
4529 : - signed variables should not overflow when flag_wrapv is not set.
4530 : */
4531 :
4532 : static void
4533 6465790 : infer_loop_bounds_from_undefined (class loop *loop, basic_block *bbs)
4534 : {
4535 6465790 : unsigned i;
4536 6465790 : gimple_stmt_iterator bsi;
4537 6465790 : basic_block bb;
4538 6465790 : bool reliable;
4539 :
4540 44526629 : for (i = 0; i < loop->num_nodes; i++)
4541 : {
4542 38060839 : bb = bbs[i];
4543 :
4544 : /* If BB is not executed in each iteration of the loop, we cannot
4545 : use the operations in it to infer reliable upper bound on the
4546 : # of iterations of the loop. However, we can use it as a guess.
4547 : Reliable guesses come only from array bounds. */
4548 38060839 : reliable = dominated_by_p (CDI_DOMINATORS, loop->latch, bb);
4549 :
4550 333141893 : for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
4551 : {
4552 257020215 : gimple *stmt = gsi_stmt (bsi);
4553 :
4554 257020215 : infer_loop_bounds_from_array (loop, stmt);
4555 :
4556 257020215 : if (reliable)
4557 : {
4558 126636479 : infer_loop_bounds_from_signedness (loop, stmt);
4559 126636479 : infer_loop_bounds_from_pointer_arith (loop, stmt);
4560 : }
4561 : }
4562 :
4563 : }
4564 6465790 : }
4565 :
4566 : /* Compare wide ints, callback for qsort. */
4567 :
4568 : static int
4569 28670 : wide_int_cmp (const void *p1, const void *p2)
4570 : {
4571 28670 : const bound_wide_int *d1 = (const bound_wide_int *) p1;
4572 28670 : const bound_wide_int *d2 = (const bound_wide_int *) p2;
4573 28670 : return wi::cmpu (*d1, *d2);
4574 : }
4575 :
4576 : /* Return index of BOUND in BOUNDS array sorted in increasing order.
4577 : Lookup by binary search. */
4578 :
4579 : static int
4580 6674 : bound_index (const vec<bound_wide_int> &bounds, const bound_wide_int &bound)
4581 : {
4582 6674 : unsigned int end = bounds.length ();
4583 : unsigned int begin = 0;
4584 :
4585 : /* Find a matching index by means of a binary search. */
4586 7626 : while (begin != end)
4587 : {
4588 7626 : unsigned int middle = (begin + end) / 2;
4589 7626 : bound_wide_int index = bounds[middle];
4590 :
4591 7626 : if (index == bound)
4592 6674 : return middle;
4593 952 : else if (wi::ltu_p (index, bound))
4594 233 : begin = middle + 1;
4595 : else
4596 : end = middle;
4597 : }
4598 0 : gcc_unreachable ();
4599 : }
4600 :
4601 : /* We recorded loop bounds only for statements dominating loop latch (and thus
4602 : executed each loop iteration). If there are any bounds on statements not
4603 : dominating the loop latch we can improve the estimate by walking the loop
4604 : body and seeing if every path from loop header to loop latch contains
4605 : some bounded statement. */
4606 :
4607 : static void
4608 6505237 : discover_iteration_bound_by_body_walk (class loop *loop)
4609 : {
4610 6505237 : class nb_iter_bound *elt;
4611 6505237 : auto_vec<bound_wide_int> bounds;
4612 6505237 : vec<vec<basic_block> > queues = vNULL;
4613 6505237 : vec<basic_block> queue = vNULL;
4614 6505237 : ptrdiff_t queue_index;
4615 6505237 : ptrdiff_t latch_index = 0;
4616 :
4617 : /* Discover what bounds may interest us. */
4618 16900479 : for (elt = loop->bounds; elt; elt = elt->next)
4619 : {
4620 10395242 : bound_wide_int bound = elt->bound;
4621 :
4622 : /* Exit terminates loop at given iteration, while non-exits produce undefined
4623 : effect on the next iteration. */
4624 10395242 : if (!elt->is_exit)
4625 : {
4626 5662801 : bound += 1;
4627 : /* If an overflow occurred, ignore the result. */
4628 5662801 : if (bound == 0)
4629 0 : continue;
4630 : }
4631 :
4632 10395242 : if (!loop->any_upper_bound
4633 10395242 : || wi::ltu_p (bound, loop->nb_iterations_upper_bound))
4634 6674 : bounds.safe_push (bound);
4635 : }
4636 :
4637 : /* Exit early if there is nothing to do. */
4638 6505237 : if (!bounds.exists ())
4639 6501563 : return;
4640 :
4641 3674 : if (dump_file && (dump_flags & TDF_DETAILS))
4642 16 : fprintf (dump_file, " Trying to walk loop body to reduce the bound.\n");
4643 :
4644 : /* Sort the bounds in decreasing order. */
4645 3674 : bounds.qsort (wide_int_cmp);
4646 :
4647 : /* For every basic block record the lowest bound that is guaranteed to
4648 : terminate the loop. */
4649 :
4650 3674 : hash_map<basic_block, ptrdiff_t> bb_bounds;
4651 18298 : for (elt = loop->bounds; elt; elt = elt->next)
4652 : {
4653 14624 : bound_wide_int bound = elt->bound;
4654 14624 : if (!elt->is_exit)
4655 : {
4656 10269 : bound += 1;
4657 : /* If an overflow occurred, ignore the result. */
4658 10269 : if (bound == 0)
4659 0 : continue;
4660 : }
4661 :
4662 14624 : if (!loop->any_upper_bound
4663 14624 : || wi::ltu_p (bound, loop->nb_iterations_upper_bound))
4664 : {
4665 6674 : ptrdiff_t index = bound_index (bounds, bound);
4666 6674 : ptrdiff_t *entry = bb_bounds.get (gimple_bb (elt->stmt));
4667 6674 : if (!entry)
4668 4816 : bb_bounds.put (gimple_bb (elt->stmt), index);
4669 1858 : else if ((ptrdiff_t)*entry > index)
4670 119 : *entry = index;
4671 : }
4672 : }
4673 :
4674 3674 : hash_map<basic_block, ptrdiff_t> block_priority;
4675 :
4676 : /* Perform shortest path discovery loop->header ... loop->latch.
4677 :
4678 : The "distance" is given by the smallest loop bound of basic block
4679 : present in the path and we look for path with largest smallest bound
4680 : on it.
4681 :
4682 : To avoid the need for fibonacci heap on double ints we simply compress
4683 : double ints into indexes to BOUNDS array and then represent the queue
4684 : as arrays of queues for every index.
4685 : Index of BOUNDS.length() means that the execution of given BB has
4686 : no bounds determined.
4687 :
4688 : VISITED is a pointer map translating basic block into smallest index
4689 : it was inserted into the priority queue with. */
4690 3674 : latch_index = -1;
4691 :
4692 : /* Start walk in loop header with index set to infinite bound. */
4693 3674 : queue_index = bounds.length ();
4694 3674 : queues.safe_grow_cleared (queue_index + 1, true);
4695 3674 : queue.safe_push (loop->header);
4696 3674 : queues[queue_index] = queue;
4697 3674 : block_priority.put (loop->header, queue_index);
4698 :
4699 14022 : for (; queue_index >= 0; queue_index--)
4700 : {
4701 10348 : if (latch_index < queue_index)
4702 : {
4703 42112 : while (queues[queue_index].length ())
4704 : {
4705 38121 : basic_block bb;
4706 38121 : ptrdiff_t bound_index = queue_index;
4707 38121 : edge e;
4708 38121 : edge_iterator ei;
4709 :
4710 38121 : queue = queues[queue_index];
4711 38121 : bb = queue.pop ();
4712 :
4713 : /* OK, we later inserted the BB with lower priority, skip it. */
4714 38121 : if (*block_priority.get (bb) > queue_index)
4715 0 : continue;
4716 :
4717 : /* See if we can improve the bound. */
4718 38121 : ptrdiff_t *entry = bb_bounds.get (bb);
4719 38121 : if (entry && *entry < bound_index)
4720 4315 : bound_index = *entry;
4721 :
4722 : /* Insert successors into the queue, watch for latch edge
4723 : and record greatest index we saw. */
4724 97367 : FOR_EACH_EDGE (e, ei, bb->succs)
4725 : {
4726 59246 : bool insert = false;
4727 :
4728 59246 : if (loop_exit_edge_p (loop, e))
4729 10409 : continue;
4730 :
4731 48837 : if (e == loop_latch_edge (loop)
4732 48837 : && latch_index < bound_index)
4733 : latch_index = bound_index;
4734 45163 : else if (!(entry = block_priority.get (e->dest)))
4735 : {
4736 35913 : insert = true;
4737 35913 : block_priority.put (e->dest, bound_index);
4738 : }
4739 9250 : else if (*entry < bound_index)
4740 : {
4741 160 : insert = true;
4742 160 : *entry = bound_index;
4743 : }
4744 :
4745 36073 : if (insert)
4746 36073 : queues[bound_index].safe_push (e->dest);
4747 : }
4748 : }
4749 : }
4750 10348 : queues[queue_index].release ();
4751 : }
4752 :
4753 3674 : gcc_assert (latch_index >= 0);
4754 3674 : if ((unsigned)latch_index < bounds.length ())
4755 : {
4756 241 : if (dump_file && (dump_flags & TDF_DETAILS))
4757 : {
4758 0 : fprintf (dump_file, "Found better loop bound ");
4759 0 : print_decu (bounds[latch_index], dump_file);
4760 0 : fprintf (dump_file, "\n");
4761 : }
4762 241 : record_niter_bound (loop, widest_int::from (bounds[latch_index],
4763 : SIGNED), false, true);
4764 : }
4765 :
4766 3674 : queues.release ();
4767 6505237 : }
4768 :
4769 : /* See if every path cross the loop goes through a statement that is known
4770 : to not execute at the last iteration. In that case we can decrease iteration
4771 : count by 1. */
4772 :
4773 : static void
4774 6505237 : maybe_lower_iteration_bound (class loop *loop)
4775 : {
4776 6505237 : hash_set<gimple *> *not_executed_last_iteration = NULL;
4777 6505237 : class nb_iter_bound *elt;
4778 6505237 : bool found_exit = false;
4779 6505237 : auto_vec<basic_block> queue;
4780 6505237 : bitmap visited;
4781 :
4782 : /* Collect all statements with interesting (i.e. lower than
4783 : nb_iterations_upper_bound) bound on them.
4784 :
4785 : TODO: Due to the way record_estimate choose estimates to store, the bounds
4786 : will be always nb_iterations_upper_bound-1. We can change this to record
4787 : also statements not dominating the loop latch and update the walk below
4788 : to the shortest path algorithm. */
4789 16900479 : for (elt = loop->bounds; elt; elt = elt->next)
4790 : {
4791 10395242 : if (!elt->is_exit
4792 10395242 : && wi::ltu_p (elt->bound, loop->nb_iterations_upper_bound))
4793 : {
4794 2186989 : if (!not_executed_last_iteration)
4795 1185043 : not_executed_last_iteration = new hash_set<gimple *>;
4796 2186989 : not_executed_last_iteration->add (elt->stmt);
4797 : }
4798 : }
4799 6505237 : if (!not_executed_last_iteration)
4800 5320194 : return;
4801 :
4802 : /* Start DFS walk in the loop header and see if we can reach the
4803 : loop latch or any of the exits (including statements with side
4804 : effects that may terminate the loop otherwise) without visiting
4805 : any of the statements known to have undefined effect on the last
4806 : iteration. */
4807 1185043 : queue.safe_push (loop->header);
4808 1185043 : visited = BITMAP_ALLOC (NULL);
4809 1185043 : bitmap_set_bit (visited, loop->header->index);
4810 1185043 : found_exit = false;
4811 :
4812 1264639 : do
4813 : {
4814 1264639 : basic_block bb = queue.pop ();
4815 1264639 : gimple_stmt_iterator gsi;
4816 1264639 : bool stmt_found = false;
4817 :
4818 : /* Loop for possible exits and statements bounding the execution. */
4819 6403540 : for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
4820 : {
4821 3935533 : gimple *stmt = gsi_stmt (gsi);
4822 3935533 : if (not_executed_last_iteration->contains (stmt))
4823 : {
4824 : stmt_found = true;
4825 61271 : break;
4826 : }
4827 3895894 : if (gimple_has_side_effects (stmt))
4828 : {
4829 : found_exit = true;
4830 : break;
4831 : }
4832 : }
4833 1264639 : if (found_exit)
4834 : break;
4835 :
4836 : /* If no bounding statement is found, continue the walk. */
4837 1243007 : if (!stmt_found)
4838 : {
4839 1203368 : edge e;
4840 1203368 : edge_iterator ei;
4841 :
4842 2019500 : FOR_EACH_EDGE (e, ei, bb->succs)
4843 : {
4844 1945291 : if (loop_exit_edge_p (loop, e)
4845 816769 : || e == loop_latch_edge (loop)
4846 : /* When exiting an inner loop, verify it is finite. */
4847 816733 : || (!flow_bb_inside_loop_p (bb->loop_father, e->dest)
4848 7553 : && !finite_loop_p (bb->loop_father))
4849 : /* When we enter an irreducible region and the entry
4850 : does not contain a bounding stmt assume it might be
4851 : infinite. */
4852 2761423 : || (bb->flags & BB_IRREDUCIBLE_LOOP))
4853 : {
4854 : found_exit = true;
4855 : break;
4856 : }
4857 816132 : if (bitmap_set_bit (visited, e->dest->index))
4858 799210 : queue.safe_push (e->dest);
4859 : }
4860 : }
4861 : }
4862 1243007 : while (queue.length () && !found_exit);
4863 :
4864 : /* If every path through the loop reach bounding statement before exit,
4865 : then we know the last iteration of the loop will have undefined effect
4866 : and we can decrease number of iterations. */
4867 :
4868 1185043 : if (!found_exit)
4869 : {
4870 34252 : if (dump_file && (dump_flags & TDF_DETAILS))
4871 68 : fprintf (dump_file, "Reducing loop iteration estimate by 1; "
4872 : "undefined statement must be executed at the last iteration.\n");
4873 68504 : record_niter_bound (loop, widest_int::from (loop->nb_iterations_upper_bound,
4874 102756 : SIGNED) - 1,
4875 : false, true);
4876 : }
4877 :
4878 1185043 : BITMAP_FREE (visited);
4879 1185043 : delete not_executed_last_iteration;
4880 6505237 : }
4881 :
4882 : /* Get expected upper bound for number of loop iterations for
4883 : BUILT_IN_EXPECT_WITH_PROBABILITY for a condition COND. */
4884 :
4885 : static tree
4886 5054676 : get_upper_bound_based_on_builtin_expr_with_prob (gcond *cond)
4887 : {
4888 5054676 : if (cond == NULL)
4889 : return NULL_TREE;
4890 :
4891 4897987 : tree lhs = gimple_cond_lhs (cond);
4892 4897987 : if (TREE_CODE (lhs) != SSA_NAME)
4893 : return NULL_TREE;
4894 :
4895 4897913 : gimple *stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (cond));
4896 5240913 : gcall *def = dyn_cast<gcall *> (stmt);
4897 186239 : if (def == NULL)
4898 : return NULL_TREE;
4899 :
4900 186239 : tree decl = gimple_call_fndecl (def);
4901 186239 : if (!decl
4902 158009 : || !fndecl_built_in_p (decl, BUILT_IN_EXPECT_WITH_PROBABILITY)
4903 186243 : || gimple_call_num_args (stmt) != 3)
4904 : return NULL_TREE;
4905 :
4906 4 : tree c = gimple_call_arg (def, 1);
4907 4 : tree condt = TREE_TYPE (lhs);
4908 4 : tree res = fold_build2 (gimple_cond_code (cond),
4909 : condt, c,
4910 : gimple_cond_rhs (cond));
4911 4 : if (TREE_CODE (res) != INTEGER_CST)
4912 : return NULL_TREE;
4913 :
4914 :
4915 4 : tree prob = gimple_call_arg (def, 2);
4916 4 : tree t = TREE_TYPE (prob);
4917 4 : tree one
4918 8 : = build_real_from_int_cst (t,
4919 4 : integer_one_node);
4920 4 : if (integer_zerop (res))
4921 0 : prob = fold_build2 (MINUS_EXPR, t, one, prob);
4922 4 : tree r = fold_build2 (RDIV_EXPR, t, one, prob);
4923 4 : if (TREE_CODE (r) != REAL_CST)
4924 : return NULL_TREE;
4925 :
4926 2 : HOST_WIDE_INT probi
4927 2 : = real_to_integer (TREE_REAL_CST_PTR (r));
4928 2 : return build_int_cst (condt, probi);
4929 : }
4930 :
4931 : /* Records estimates on numbers of iterations of LOOP. If USE_UNDEFINED_P
4932 : is true also use estimates derived from undefined behavior. */
4933 :
4934 : void
4935 26913431 : estimate_numbers_of_iterations (class loop *loop)
4936 : {
4937 26913431 : tree niter, type;
4938 26913431 : unsigned i;
4939 26913431 : class tree_niter_desc niter_desc;
4940 26913431 : edge ex;
4941 26913431 : widest_int bound;
4942 26913431 : edge likely_exit;
4943 :
4944 : /* Give up if we already have tried to compute an estimation. */
4945 26913431 : if (loop->estimate_state != EST_NOT_COMPUTED)
4946 20408194 : return;
4947 :
4948 6505237 : if (dump_file && (dump_flags & TDF_DETAILS))
4949 13796 : fprintf (dump_file, "Estimating # of iterations of loop %d\n", loop->num);
4950 :
4951 6505237 : loop->estimate_state = EST_AVAILABLE;
4952 :
4953 6505237 : sreal nit;
4954 6505237 : bool reliable;
4955 :
4956 : /* If we have a measured profile, use it to estimate the number of
4957 : iterations. Normally this is recorded by branch_prob right after
4958 : reading the profile. In case we however found a new loop, record the
4959 : information here.
4960 :
4961 : Explicitly check for profile status so we do not report
4962 : wrong prediction hitrates for guessed loop iterations heuristics.
4963 : Do not recompute already recorded bounds - we ought to be better on
4964 : updating iteration bounds than updating profile in general and thus
4965 : recomputing iteration bounds later in the compilation process will just
4966 : introduce random roundoff errors. */
4967 6505237 : if (!loop->any_estimate
4968 4440937 : && expected_loop_iterations_by_profile (loop, &nit, &reliable)
4969 10062370 : && reliable)
4970 : {
4971 11 : bound = nit.to_nearest_int ();
4972 11 : record_niter_bound (loop, bound, true, false);
4973 : }
4974 :
4975 : /* Ensure that loop->nb_iterations is computed if possible. If it turns out
4976 : to be constant, we avoid undefined behavior implied bounds and instead
4977 : diagnose those loops with -Waggressive-loop-optimizations. */
4978 6505237 : number_of_latch_executions (loop);
4979 :
4980 6505237 : basic_block *body = get_loop_body (loop);
4981 6505237 : auto_vec<edge> exits = get_loop_exit_edges (loop, body);
4982 6505237 : likely_exit = single_likely_exit (loop, exits);
4983 18143831 : FOR_EACH_VEC_ELT (exits, i, ex)
4984 : {
4985 11638594 : if (ex == likely_exit)
4986 : {
4987 5054676 : gimple *stmt = *gsi_last_bb (ex->src);
4988 5054676 : if (stmt != NULL)
4989 : {
4990 5054676 : gcond *cond = dyn_cast<gcond *> (stmt);
4991 5054676 : tree niter_bound
4992 5054676 : = get_upper_bound_based_on_builtin_expr_with_prob (cond);
4993 5054676 : if (niter_bound != NULL_TREE)
4994 : {
4995 2 : widest_int max = derive_constant_upper_bound (niter_bound);
4996 2 : record_estimate (loop, niter_bound, max, cond,
4997 : true, true, false);
4998 2 : }
4999 : }
5000 : }
5001 :
5002 11638594 : if (!number_of_iterations_exit (loop, ex, &niter_desc,
5003 : false, false, body))
5004 6906139 : continue;
5005 :
5006 4732455 : niter = niter_desc.niter;
5007 4732455 : type = TREE_TYPE (niter);
5008 4732455 : if (TREE_CODE (niter_desc.may_be_zero) != INTEGER_CST)
5009 735238 : niter = build3 (COND_EXPR, type, niter_desc.may_be_zero,
5010 : build_int_cst (type, 0),
5011 : niter);
5012 4732455 : record_estimate (loop, niter, niter_desc.max,
5013 : last_nondebug_stmt (ex->src),
5014 : true, ex == likely_exit, true);
5015 4732455 : record_control_iv (loop, &niter_desc);
5016 : }
5017 :
5018 6505237 : if (flag_aggressive_loop_optimizations)
5019 6465790 : infer_loop_bounds_from_undefined (loop, body);
5020 6505237 : free (body);
5021 :
5022 6505237 : discover_iteration_bound_by_body_walk (loop);
5023 :
5024 6505237 : maybe_lower_iteration_bound (loop);
5025 :
5026 : /* If we know the exact number of iterations of this loop, try to
5027 : not break code with undefined behavior by not recording smaller
5028 : maximum number of iterations. */
5029 6505237 : if (loop->nb_iterations
5030 6505237 : && TREE_CODE (loop->nb_iterations) == INTEGER_CST
5031 13010474 : && (wi::min_precision (wi::to_widest (loop->nb_iterations), SIGNED)
5032 2000839 : <= bound_wide_int ().get_precision ()))
5033 : {
5034 2000839 : loop->any_upper_bound = true;
5035 2000839 : loop->nb_iterations_upper_bound
5036 2000839 : = bound_wide_int::from (wi::to_widest (loop->nb_iterations), SIGNED);
5037 : }
5038 26913445 : }
5039 :
5040 : /* Sets NIT to the estimated number of executions of the latch of the
5041 : LOOP. If CONSERVATIVE is true, we must be sure that NIT is at least as
5042 : large as the number of iterations. If we have no reliable estimate,
5043 : the function returns false, otherwise returns true. */
5044 :
5045 : bool
5046 9883585 : estimated_loop_iterations (class loop *loop, widest_int *nit)
5047 : {
5048 : /* When SCEV information is available, try to update loop iterations
5049 : estimate. Otherwise just return whatever we recorded earlier. */
5050 9883585 : if (scev_initialized_p ())
5051 9883585 : estimate_numbers_of_iterations (loop);
5052 :
5053 9883585 : return (get_estimated_loop_iterations (loop, nit));
5054 : }
5055 :
5056 : /* Similar to estimated_loop_iterations, but returns the estimate only
5057 : if it fits to HOST_WIDE_INT. If this is not the case, or the estimate
5058 : on the number of iterations of LOOP could not be derived, returns -1. */
5059 :
5060 : HOST_WIDE_INT
5061 9621978 : estimated_loop_iterations_int (class loop *loop)
5062 : {
5063 9621978 : widest_int nit;
5064 9621978 : HOST_WIDE_INT hwi_nit;
5065 :
5066 9621978 : if (!estimated_loop_iterations (loop, &nit))
5067 : return -1;
5068 :
5069 3989545 : if (!wi::fits_shwi_p (nit))
5070 : return -1;
5071 3989539 : hwi_nit = nit.to_shwi ();
5072 :
5073 3989539 : return hwi_nit < 0 ? -1 : hwi_nit;
5074 9621978 : }
5075 :
5076 :
5077 : /* Sets NIT to an upper bound for the maximum number of executions of the
5078 : latch of the LOOP. If we have no reliable estimate, the function returns
5079 : false, otherwise returns true. */
5080 :
5081 : bool
5082 8839331 : max_loop_iterations (class loop *loop, widest_int *nit)
5083 : {
5084 : /* When SCEV information is available, try to update loop iterations
5085 : estimate. Otherwise just return whatever we recorded earlier. */
5086 8839331 : if (scev_initialized_p ())
5087 8826704 : estimate_numbers_of_iterations (loop);
5088 :
5089 8839331 : return get_max_loop_iterations (loop, nit);
5090 : }
5091 :
5092 : /* Similar to max_loop_iterations, but returns the estimate only
5093 : if it fits to HOST_WIDE_INT. If this is not the case, or the estimate
5094 : on the number of iterations of LOOP could not be derived, returns -1. */
5095 :
5096 : HOST_WIDE_INT
5097 2244808 : max_loop_iterations_int (class loop *loop)
5098 : {
5099 2244808 : widest_int nit;
5100 2244808 : HOST_WIDE_INT hwi_nit;
5101 :
5102 2244808 : if (!max_loop_iterations (loop, &nit))
5103 : return -1;
5104 :
5105 1702009 : if (!wi::fits_shwi_p (nit))
5106 : return -1;
5107 1632422 : hwi_nit = nit.to_shwi ();
5108 :
5109 1632422 : return hwi_nit < 0 ? -1 : hwi_nit;
5110 2244808 : }
5111 :
5112 : /* Sets NIT to an likely upper bound for the maximum number of executions of the
5113 : latch of the LOOP. If we have no reliable estimate, the function returns
5114 : false, otherwise returns true. */
5115 :
5116 : bool
5117 362699 : likely_max_loop_iterations (class loop *loop, widest_int *nit)
5118 : {
5119 : /* When SCEV information is available, try to update loop iterations
5120 : estimate. Otherwise just return whatever we recorded earlier. */
5121 362699 : if (scev_initialized_p ())
5122 362699 : estimate_numbers_of_iterations (loop);
5123 :
5124 362699 : return get_likely_max_loop_iterations (loop, nit);
5125 : }
5126 :
5127 : /* Similar to max_loop_iterations, but returns the estimate only
5128 : if it fits to HOST_WIDE_INT. If this is not the case, or the estimate
5129 : on the number of iterations of LOOP could not be derived, returns -1. */
5130 :
5131 : HOST_WIDE_INT
5132 110143 : likely_max_loop_iterations_int (class loop *loop)
5133 : {
5134 110143 : widest_int nit;
5135 110143 : HOST_WIDE_INT hwi_nit;
5136 :
5137 110143 : if (!likely_max_loop_iterations (loop, &nit))
5138 : return -1;
5139 :
5140 89905 : if (!wi::fits_shwi_p (nit))
5141 : return -1;
5142 82232 : hwi_nit = nit.to_shwi ();
5143 :
5144 82232 : return hwi_nit < 0 ? -1 : hwi_nit;
5145 110143 : }
5146 :
5147 : /* Returns an estimate for the number of executions of statements
5148 : in the LOOP. For statements before the loop exit, this exceeds
5149 : the number of execution of the latch by one. */
5150 :
5151 : HOST_WIDE_INT
5152 9448243 : estimated_stmt_executions_int (class loop *loop)
5153 : {
5154 9448243 : HOST_WIDE_INT nit = estimated_loop_iterations_int (loop);
5155 9448243 : HOST_WIDE_INT snit;
5156 :
5157 9448243 : if (nit == -1)
5158 : return -1;
5159 :
5160 3926113 : snit = (HOST_WIDE_INT) ((unsigned HOST_WIDE_INT) nit + 1);
5161 :
5162 : /* If the computation overflows, return -1. */
5163 3926113 : return snit < 0 ? -1 : snit;
5164 : }
5165 :
5166 : /* Sets NIT to the maximum number of executions of the latch of the
5167 : LOOP, plus one. If we have no reliable estimate, the function returns
5168 : false, otherwise returns true. */
5169 :
5170 : bool
5171 154 : max_stmt_executions (class loop *loop, widest_int *nit)
5172 : {
5173 154 : widest_int nit_minus_one;
5174 :
5175 154 : if (!max_loop_iterations (loop, nit))
5176 : return false;
5177 :
5178 154 : nit_minus_one = *nit;
5179 :
5180 154 : *nit += 1;
5181 :
5182 154 : return wi::gtu_p (*nit, nit_minus_one);
5183 154 : }
5184 :
5185 : /* Sets NIT to the estimated maximum number of executions of the latch of the
5186 : LOOP, plus one. If we have no likely estimate, the function returns
5187 : false, otherwise returns true. */
5188 :
5189 : bool
5190 252556 : likely_max_stmt_executions (class loop *loop, widest_int *nit)
5191 : {
5192 252556 : widest_int nit_minus_one;
5193 :
5194 252556 : if (!likely_max_loop_iterations (loop, nit))
5195 : return false;
5196 :
5197 143295 : nit_minus_one = *nit;
5198 :
5199 143295 : *nit += 1;
5200 :
5201 143295 : return wi::gtu_p (*nit, nit_minus_one);
5202 252556 : }
5203 :
5204 : /* Sets NIT to the estimated number of executions of the latch of the
5205 : LOOP, plus one. If we have no reliable estimate, the function returns
5206 : false, otherwise returns true. */
5207 :
5208 : bool
5209 261607 : estimated_stmt_executions (class loop *loop, widest_int *nit)
5210 : {
5211 261607 : widest_int nit_minus_one;
5212 :
5213 261607 : if (!estimated_loop_iterations (loop, nit))
5214 : return false;
5215 :
5216 7744 : nit_minus_one = *nit;
5217 :
5218 7744 : *nit += 1;
5219 :
5220 7744 : return wi::gtu_p (*nit, nit_minus_one);
5221 261607 : }
5222 :
5223 : /* Records estimates on numbers of iterations of loops. */
5224 :
5225 : void
5226 1220486 : estimate_numbers_of_iterations (function *fn)
5227 : {
5228 7345759 : for (auto loop : loops_list (fn, 0))
5229 3684301 : estimate_numbers_of_iterations (loop);
5230 1220486 : }
5231 :
5232 : /* Returns true if statement S1 dominates statement S2. */
5233 :
5234 : bool
5235 2298056 : stmt_dominates_stmt_p (gimple *s1, gimple *s2)
5236 : {
5237 2298056 : basic_block bb1 = gimple_bb (s1), bb2 = gimple_bb (s2);
5238 :
5239 2298056 : if (!bb1
5240 2298056 : || s1 == s2)
5241 : return true;
5242 :
5243 2290020 : if (bb1 == bb2)
5244 : {
5245 839972 : gimple_stmt_iterator bsi;
5246 :
5247 839972 : if (gimple_code (s2) == GIMPLE_PHI)
5248 : return false;
5249 :
5250 537513 : if (gimple_code (s1) == GIMPLE_PHI)
5251 : return true;
5252 :
5253 19524307 : for (bsi = gsi_start_bb (bb1); gsi_stmt (bsi) != s2; gsi_next (&bsi))
5254 18711723 : if (gsi_stmt (bsi) == s1)
5255 : return true;
5256 :
5257 : return false;
5258 : }
5259 :
5260 1450048 : return dominated_by_p (CDI_DOMINATORS, bb2, bb1);
5261 : }
5262 :
5263 : /* Returns true when we can prove that the number of executions of
5264 : STMT in the loop is at most NITER, according to the bound on
5265 : the number of executions of the statement NITER_BOUND->stmt recorded in
5266 : NITER_BOUND and fact that NITER_BOUND->stmt dominate STMT.
5267 :
5268 : ??? This code can become quite a CPU hog - we can have many bounds,
5269 : and large basic block forcing stmt_dominates_stmt_p to be queried
5270 : many times on a large basic blocks, so the whole thing is O(n^2)
5271 : for scev_probably_wraps_p invocation (that can be done n times).
5272 :
5273 : It would make more sense (and give better answers) to remember BB
5274 : bounds computed by discover_iteration_bound_by_body_walk. */
5275 :
5276 : static bool
5277 2454207 : n_of_executions_at_most (gimple *stmt,
5278 : class nb_iter_bound *niter_bound,
5279 : tree niter)
5280 : {
5281 2454207 : widest_int bound = widest_int::from (niter_bound->bound, SIGNED);
5282 2454207 : tree nit_type = TREE_TYPE (niter), e;
5283 2454207 : enum tree_code cmp;
5284 :
5285 2454207 : gcc_assert (TYPE_UNSIGNED (nit_type));
5286 :
5287 : /* If the bound does not even fit into NIT_TYPE, it cannot tell us that
5288 : the number of iterations is small. */
5289 2454207 : if (!wi::fits_to_tree_p (bound, nit_type))
5290 : return false;
5291 :
5292 : /* We know that NITER_BOUND->stmt is executed at most NITER_BOUND->bound + 1
5293 : times. This means that:
5294 :
5295 : -- if NITER_BOUND->is_exit is true, then everything after
5296 : it at most NITER_BOUND->bound times.
5297 :
5298 : -- If NITER_BOUND->is_exit is false, then if we can prove that when STMT
5299 : is executed, then NITER_BOUND->stmt is executed as well in the same
5300 : iteration then STMT is executed at most NITER_BOUND->bound + 1 times.
5301 :
5302 : If we can determine that NITER_BOUND->stmt is always executed
5303 : after STMT, then STMT is executed at most NITER_BOUND->bound + 2 times.
5304 : We conclude that if both statements belong to the same
5305 : basic block and STMT is before NITER_BOUND->stmt and there are no
5306 : statements with side effects in between. */
5307 :
5308 2298056 : if (niter_bound->is_exit)
5309 : {
5310 861054 : if (stmt == niter_bound->stmt
5311 861054 : || !stmt_dominates_stmt_p (niter_bound->stmt, stmt))
5312 746518 : return false;
5313 : cmp = GE_EXPR;
5314 : }
5315 : else
5316 : {
5317 1437002 : if (!stmt_dominates_stmt_p (niter_bound->stmt, stmt))
5318 : {
5319 586701 : gimple_stmt_iterator bsi;
5320 586701 : if (gimple_bb (stmt) != gimple_bb (niter_bound->stmt)
5321 248277 : || gimple_code (stmt) == GIMPLE_PHI
5322 770540 : || gimple_code (niter_bound->stmt) == GIMPLE_PHI)
5323 408243 : return false;
5324 :
5325 : /* By stmt_dominates_stmt_p we already know that STMT appears
5326 : before NITER_BOUND->STMT. Still need to test that the loop
5327 : cannot be terinated by a side effect in between. */
5328 7985706 : for (bsi = gsi_for_stmt (stmt); gsi_stmt (bsi) != niter_bound->stmt;
5329 7801867 : gsi_next (&bsi))
5330 7802778 : if (gimple_has_side_effects (gsi_stmt (bsi)))
5331 : return false;
5332 182928 : bound += 1;
5333 361386 : if (bound == 0
5334 182928 : || !wi::fits_to_tree_p (bound, nit_type))
5335 4470 : return false;
5336 : }
5337 : cmp = GT_EXPR;
5338 : }
5339 :
5340 1143295 : e = fold_binary (cmp, boolean_type_node,
5341 : niter, wide_int_to_tree (nit_type, bound));
5342 1143295 : return e && integer_nonzerop (e);
5343 2454207 : }
5344 :
5345 : /* Returns true if the arithmetics in TYPE can be assumed not to wrap. */
5346 :
5347 : bool
5348 86391227 : nowrap_type_p (tree type)
5349 : {
5350 11695704 : if (ANY_INTEGRAL_TYPE_P (type)
5351 86391227 : && TYPE_OVERFLOW_UNDEFINED (type))
5352 : return true;
5353 :
5354 42995502 : if (POINTER_TYPE_P (type))
5355 11695704 : return true;
5356 :
5357 : return false;
5358 : }
5359 :
5360 : /* Return true if we can prove LOOP is exited before evolution of induction
5361 : variable {BASE, STEP} overflows with respect to its type bound. */
5362 :
5363 : static bool
5364 3437115 : loop_exits_before_overflow (tree base, tree step,
5365 : gimple *at_stmt, class loop *loop)
5366 : {
5367 3437115 : widest_int niter;
5368 3437115 : struct control_iv *civ;
5369 3437115 : class nb_iter_bound *bound;
5370 3437115 : tree e, delta, step_abs, unsigned_base;
5371 3437115 : tree type = TREE_TYPE (step);
5372 3437115 : tree unsigned_type, valid_niter;
5373 :
5374 : /* Compute the number of iterations before we reach the bound of the
5375 : type, and verify that the loop is exited before this occurs. */
5376 3437115 : unsigned_type = unsigned_type_for (type);
5377 3437115 : unsigned_base = fold_convert (unsigned_type, base);
5378 :
5379 3437115 : if (tree_int_cst_sign_bit (step))
5380 : {
5381 490509 : tree extreme = fold_convert (unsigned_type,
5382 : lower_bound_in_type (type, type));
5383 490509 : delta = fold_build2 (MINUS_EXPR, unsigned_type, unsigned_base, extreme);
5384 490509 : step_abs = fold_build1 (NEGATE_EXPR, unsigned_type,
5385 : fold_convert (unsigned_type, step));
5386 : }
5387 : else
5388 : {
5389 2946606 : tree extreme = fold_convert (unsigned_type,
5390 : upper_bound_in_type (type, type));
5391 2946606 : delta = fold_build2 (MINUS_EXPR, unsigned_type, extreme, unsigned_base);
5392 2946606 : step_abs = fold_convert (unsigned_type, step);
5393 : }
5394 :
5395 3437115 : valid_niter = fold_build2 (FLOOR_DIV_EXPR, unsigned_type, delta, step_abs);
5396 :
5397 3437115 : estimate_numbers_of_iterations (loop);
5398 :
5399 3437115 : if (max_loop_iterations (loop, &niter)
5400 2926222 : && wi::fits_to_tree_p (niter, TREE_TYPE (valid_niter))
5401 2744145 : && (e = fold_binary (GT_EXPR, boolean_type_node, valid_niter,
5402 : wide_int_to_tree (TREE_TYPE (valid_niter),
5403 : niter))) != NULL
5404 6098133 : && integer_nonzerop (e))
5405 1135776 : return true;
5406 2301339 : if (at_stmt)
5407 3774161 : for (bound = loop->bounds; bound; bound = bound->next)
5408 : {
5409 2454207 : if (n_of_executions_at_most (at_stmt, bound, valid_niter))
5410 : return true;
5411 : }
5412 :
5413 : /* Try to prove loop is exited before {base, step} overflows with the
5414 : help of analyzed loop control IV. This is done only for IVs with
5415 : constant step because otherwise we don't have the information. */
5416 2283001 : if (TREE_CODE (step) == INTEGER_CST)
5417 : {
5418 3420607 : for (civ = loop->control_ivs; civ; civ = civ->next)
5419 : {
5420 1322399 : enum tree_code code;
5421 1322399 : tree civ_type = TREE_TYPE (civ->step);
5422 :
5423 : /* Have to consider type difference because operand_equal_p ignores
5424 : that for constants. */
5425 1322399 : if (TYPE_UNSIGNED (type) != TYPE_UNSIGNED (civ_type)
5426 1322399 : || element_precision (type) != element_precision (civ_type))
5427 770146 : continue;
5428 :
5429 : /* Only consider control IV with same step. */
5430 552253 : if (!operand_equal_p (step, civ->step, 0))
5431 202767 : continue;
5432 :
5433 : /* Done proving if this is a no-overflow control IV. */
5434 349486 : if (operand_equal_p (base, civ->base, 0))
5435 : return true;
5436 :
5437 : /* Control IV is recorded after expanding simple operations,
5438 : Here we expand base and compare it too. */
5439 241504 : tree expanded_base = expand_simple_operations (base);
5440 241504 : if (operand_equal_p (expanded_base, civ->base, 0))
5441 : return true;
5442 :
5443 : /* If this is a before stepping control IV, in other words, we have
5444 :
5445 : {civ_base, step} = {base + step, step}
5446 :
5447 : Because civ {base + step, step} doesn't overflow during loop
5448 : iterations, {base, step} will not overflow if we can prove the
5449 : operation "base + step" does not overflow. Specifically, we try
5450 : to prove below conditions are satisfied:
5451 :
5452 : base <= UPPER_BOUND (type) - step ;;step > 0
5453 : base >= LOWER_BOUND (type) - step ;;step < 0
5454 :
5455 : by proving the reverse conditions are false using loop's initial
5456 : condition. */
5457 209149 : if (POINTER_TYPE_P (TREE_TYPE (base)))
5458 : code = POINTER_PLUS_EXPR;
5459 : else
5460 : code = PLUS_EXPR;
5461 :
5462 209149 : tree stepped = fold_build2 (code, TREE_TYPE (base), base, step);
5463 209149 : tree expanded_stepped = fold_build2 (code, TREE_TYPE (base),
5464 : expanded_base, step);
5465 209149 : if (operand_equal_p (stepped, civ->base, 0)
5466 209149 : || operand_equal_p (expanded_stepped, civ->base, 0))
5467 : {
5468 55073 : tree extreme;
5469 :
5470 55073 : if (tree_int_cst_sign_bit (step))
5471 : {
5472 13821 : code = LT_EXPR;
5473 13821 : extreme = lower_bound_in_type (type, type);
5474 : }
5475 : else
5476 : {
5477 41252 : code = GT_EXPR;
5478 41252 : extreme = upper_bound_in_type (type, type);
5479 : }
5480 55073 : extreme = fold_build2 (MINUS_EXPR, type, extreme, step);
5481 55073 : e = fold_build2 (code, boolean_type_node, base, extreme);
5482 55073 : e = simplify_using_initial_conditions (loop, e);
5483 55073 : if (integer_zerop (e))
5484 : return true;
5485 : }
5486 : }
5487 : }
5488 :
5489 : return false;
5490 3437115 : }
5491 :
5492 : /* VAR is scev variable whose evolution part is constant STEP, this function
5493 : proves that VAR can't overflow by using value range info. If VAR's value
5494 : range is [MIN, MAX], it can be proven by:
5495 : MAX + step doesn't overflow ; if step > 0
5496 : or
5497 : MIN + step doesn't underflow ; if step < 0.
5498 :
5499 : We can only do this if var is computed in every loop iteration, i.e, var's
5500 : definition has to dominate loop latch. Consider below example:
5501 :
5502 : {
5503 : unsigned int i;
5504 :
5505 : <bb 3>:
5506 :
5507 : <bb 4>:
5508 : # RANGE [0, 4294967294] NONZERO 65535
5509 : # i_21 = PHI <0(3), i_18(9)>
5510 : if (i_21 != 0)
5511 : goto <bb 6>;
5512 : else
5513 : goto <bb 8>;
5514 :
5515 : <bb 6>:
5516 : # RANGE [0, 65533] NONZERO 65535
5517 : _6 = i_21 + 4294967295;
5518 : # RANGE [0, 65533] NONZERO 65535
5519 : _7 = (long unsigned int) _6;
5520 : # RANGE [0, 524264] NONZERO 524280
5521 : _8 = _7 * 8;
5522 : # PT = nonlocal escaped
5523 : _9 = a_14 + _8;
5524 : *_9 = 0;
5525 :
5526 : <bb 8>:
5527 : # RANGE [1, 65535] NONZERO 65535
5528 : i_18 = i_21 + 1;
5529 : if (i_18 >= 65535)
5530 : goto <bb 10>;
5531 : else
5532 : goto <bb 9>;
5533 :
5534 : <bb 9>:
5535 : goto <bb 4>;
5536 :
5537 : <bb 10>:
5538 : return;
5539 : }
5540 :
5541 : VAR _6 doesn't overflow only with pre-condition (i_21 != 0), here we
5542 : can't use _6 to prove no-overflow for _7. In fact, var _7 takes value
5543 : sequence (4294967295, 0, 1, ..., 65533) in loop life time, rather than
5544 : (4294967295, 4294967296, ...). */
5545 :
5546 : static bool
5547 308902 : scev_var_range_cant_overflow (tree var, tree step, class loop *loop)
5548 : {
5549 308902 : tree type;
5550 308902 : wide_int minv, maxv, diff, step_wi;
5551 :
5552 308902 : if (TREE_CODE (step) != INTEGER_CST || !INTEGRAL_TYPE_P (TREE_TYPE (var)))
5553 : return false;
5554 :
5555 : /* Check if VAR evaluates in every loop iteration. It's not the case
5556 : if VAR is default definition or does not dominate loop's latch. */
5557 308902 : basic_block def_bb = gimple_bb (SSA_NAME_DEF_STMT (var));
5558 308902 : if (!def_bb || !dominated_by_p (CDI_DOMINATORS, loop->latch, def_bb))
5559 2642 : return false;
5560 :
5561 306260 : int_range_max r (TREE_TYPE (var));
5562 612520 : get_range_query (cfun)->range_of_expr (r, var);
5563 306260 : if (r.varying_p () || r.undefined_p ())
5564 : return false;
5565 :
5566 : /* VAR is a scev whose evolution part is STEP and value range info
5567 : is [MIN, MAX], we can prove its no-overflowness by conditions:
5568 :
5569 : type_MAX - MAX >= step ; if step > 0
5570 : MIN - type_MIN >= |step| ; if step < 0.
5571 :
5572 : Or VAR must take value outside of value range, which is not true. */
5573 114489 : step_wi = wi::to_wide (step);
5574 114489 : type = TREE_TYPE (var);
5575 114489 : if (tree_int_cst_sign_bit (step))
5576 : {
5577 6841 : diff = r.lower_bound () - wi::to_wide (lower_bound_in_type (type, type));
5578 6841 : step_wi = - step_wi;
5579 : }
5580 : else
5581 107648 : diff = wi::to_wide (upper_bound_in_type (type, type)) - r.upper_bound ();
5582 :
5583 114489 : return (wi::geu_p (diff, step_wi));
5584 615162 : }
5585 :
5586 : /* Return false only when the induction variable BASE + STEP * I is
5587 : known to not overflow: i.e. when the number of iterations is small
5588 : enough with respect to the step and initial condition in order to
5589 : keep the evolution confined in TYPEs bounds. Return true when the
5590 : iv is known to overflow or when the property is not computable.
5591 :
5592 : USE_OVERFLOW_SEMANTICS is true if this function should assume that
5593 : the rules for overflow of the given language apply (e.g., that signed
5594 : arithmetics in C does not overflow).
5595 :
5596 : If VAR is a ssa variable, this function also returns false if VAR can
5597 : be proven not overflow with value range info. */
5598 :
5599 : bool
5600 7802614 : scev_probably_wraps_p (tree var, tree base, tree step,
5601 : gimple *at_stmt, class loop *loop,
5602 : bool use_overflow_semantics)
5603 : {
5604 : /* FIXME: We really need something like
5605 : http://gcc.gnu.org/ml/gcc-patches/2005-06/msg02025.html.
5606 :
5607 : We used to test for the following situation that frequently appears
5608 : during address arithmetics:
5609 :
5610 : D.1621_13 = (long unsigned intD.4) D.1620_12;
5611 : D.1622_14 = D.1621_13 * 8;
5612 : D.1623_15 = (doubleD.29 *) D.1622_14;
5613 :
5614 : And derived that the sequence corresponding to D_14
5615 : can be proved to not wrap because it is used for computing a
5616 : memory access; however, this is not really the case -- for example,
5617 : if D_12 = (unsigned char) [254,+,1], then D_14 has values
5618 : 2032, 2040, 0, 8, ..., but the code is still legal. */
5619 :
5620 7802614 : if (chrec_contains_undetermined (base)
5621 7802614 : || chrec_contains_undetermined (step))
5622 0 : return true;
5623 :
5624 7802614 : if (integer_zerop (step))
5625 : return false;
5626 :
5627 : /* If we can use the fact that signed and pointer arithmetics does not
5628 : wrap, we are done. */
5629 7802614 : if (use_overflow_semantics && nowrap_type_p (TREE_TYPE (base)))
5630 : return false;
5631 :
5632 : /* To be able to use estimates on number of iterations of the loop,
5633 : we must have an upper bound on the absolute value of the step. */
5634 3986701 : if (TREE_CODE (step) != INTEGER_CST)
5635 : return true;
5636 :
5637 : /* Check if var can be proven not overflow with value range info. */
5638 310582 : if (var && TREE_CODE (var) == SSA_NAME
5639 3848573 : && scev_var_range_cant_overflow (var, step, loop))
5640 : return false;
5641 :
5642 3437115 : if (loop_exits_before_overflow (base, step, at_stmt, loop))
5643 : return false;
5644 :
5645 : /* Check the nonwrapping flag, which may be set by niter analysis (e.g., the
5646 : above loop exits before overflow). */
5647 2098208 : if (var && nonwrapping_chrec_p (analyze_scalar_evolution (loop, var)))
5648 : return false;
5649 :
5650 : /* At this point we still don't have a proof that the iv does not
5651 : overflow: give up. */
5652 : return true;
5653 : }
5654 :
5655 : /* Frees the information on upper bounds on numbers of iterations of LOOP. */
5656 :
5657 : void
5658 55191644 : free_numbers_of_iterations_estimates (class loop *loop)
5659 : {
5660 55191644 : struct control_iv *civ;
5661 55191644 : class nb_iter_bound *bound;
5662 :
5663 55191644 : loop->nb_iterations = NULL;
5664 55191644 : loop->estimate_state = EST_NOT_COMPUTED;
5665 65300967 : for (bound = loop->bounds; bound;)
5666 : {
5667 10109323 : class nb_iter_bound *next = bound->next;
5668 10109323 : ggc_free (bound);
5669 10109323 : bound = next;
5670 : }
5671 55191644 : loop->bounds = NULL;
5672 :
5673 59630602 : for (civ = loop->control_ivs; civ;)
5674 : {
5675 4438958 : struct control_iv *next = civ->next;
5676 4438958 : ggc_free (civ);
5677 4438958 : civ = next;
5678 : }
5679 55191644 : loop->control_ivs = NULL;
5680 55191644 : }
5681 :
5682 : /* Frees the information on upper bounds on numbers of iterations of loops. */
5683 :
5684 : void
5685 71322753 : free_numbers_of_iterations_estimates (function *fn)
5686 : {
5687 268499176 : for (auto loop : loops_list (fn, 0))
5688 54530917 : free_numbers_of_iterations_estimates (loop);
5689 71322753 : }
5690 :
5691 : /* Substitute value VAL for ssa name NAME inside expressions held
5692 : at LOOP. */
5693 :
5694 : void
5695 123166694 : substitute_in_loop_info (class loop *loop, tree name, tree val)
5696 : {
5697 123166694 : loop->nb_iterations = simplify_replace_tree (loop->nb_iterations, name, val);
5698 123166694 : }
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