2 * Copyright 2008-2009 Katholieke Universiteit Leuven
3 * Copyright 2010 INRIA Saclay
4 * Copyright 2012-2013 Ecole Normale Superieure
5 * Copyright 2014 INRIA Rocquencourt
6 * Copyright 2016 INRIA Paris
8 * Use of this software is governed by the MIT license
10 * Written by Sven Verdoolaege, K.U.Leuven, Departement
11 * Computerwetenschappen, Celestijnenlaan 200A, B-3001 Leuven, Belgium
12 * and INRIA Saclay - Ile-de-France, Parc Club Orsay Universite,
13 * ZAC des vignes, 4 rue Jacques Monod, 91893 Orsay, France
14 * and Ecole Normale Superieure, 45 rue d’Ulm, 75230 Paris, France
15 * and Inria Paris - Rocquencourt, Domaine de Voluceau - Rocquencourt,
16 * B.P. 105 - 78153 Le Chesnay, France
17 * and Centre de Recherche Inria de Paris, 2 rue Simone Iff - Voie DQ12,
18 * CS 42112, 75589 Paris Cedex 12, France
21 #include <isl_ctx_private.h>
22 #include "isl_map_private.h"
24 #include <isl/options.h>
26 #include <isl_mat_private.h>
27 #include <isl_local_space_private.h>
28 #include <isl_vec_private.h>
29 #include <isl_aff_private.h>
30 #include <isl_equalities.h>
32 #include <set_to_map.c>
33 #include <set_from_map.c>
35 #define STATUS_ERROR -1
36 #define STATUS_REDUNDANT 1
37 #define STATUS_VALID 2
38 #define STATUS_SEPARATE 3
40 #define STATUS_ADJ_EQ 5
41 #define STATUS_ADJ_INEQ 6
43 static int status_in(isl_int
*ineq
, struct isl_tab
*tab
)
45 enum isl_ineq_type type
= isl_tab_ineq_type(tab
, ineq
);
48 case isl_ineq_error
: return STATUS_ERROR
;
49 case isl_ineq_redundant
: return STATUS_VALID
;
50 case isl_ineq_separate
: return STATUS_SEPARATE
;
51 case isl_ineq_cut
: return STATUS_CUT
;
52 case isl_ineq_adj_eq
: return STATUS_ADJ_EQ
;
53 case isl_ineq_adj_ineq
: return STATUS_ADJ_INEQ
;
57 /* Compute the position of the equalities of basic map "bmap_i"
58 * with respect to the basic map represented by "tab_j".
59 * The resulting array has twice as many entries as the number
60 * of equalities corresponding to the two inequalties to which
61 * each equality corresponds.
63 static int *eq_status_in(__isl_keep isl_basic_map
*bmap_i
,
64 struct isl_tab
*tab_j
)
67 int *eq
= isl_calloc_array(bmap_i
->ctx
, int, 2 * bmap_i
->n_eq
);
73 dim
= isl_basic_map_total_dim(bmap_i
);
74 for (k
= 0; k
< bmap_i
->n_eq
; ++k
) {
75 for (l
= 0; l
< 2; ++l
) {
76 isl_seq_neg(bmap_i
->eq
[k
], bmap_i
->eq
[k
], 1+dim
);
77 eq
[2 * k
+ l
] = status_in(bmap_i
->eq
[k
], tab_j
);
78 if (eq
[2 * k
+ l
] == STATUS_ERROR
)
81 if (eq
[2 * k
] == STATUS_SEPARATE
||
82 eq
[2 * k
+ 1] == STATUS_SEPARATE
)
92 /* Compute the position of the inequalities of basic map "bmap_i"
93 * (also represented by "tab_i", if not NULL) with respect to the basic map
94 * represented by "tab_j".
96 static int *ineq_status_in(__isl_keep isl_basic_map
*bmap_i
,
97 struct isl_tab
*tab_i
, struct isl_tab
*tab_j
)
100 unsigned n_eq
= bmap_i
->n_eq
;
101 int *ineq
= isl_calloc_array(bmap_i
->ctx
, int, bmap_i
->n_ineq
);
106 for (k
= 0; k
< bmap_i
->n_ineq
; ++k
) {
107 if (tab_i
&& isl_tab_is_redundant(tab_i
, n_eq
+ k
)) {
108 ineq
[k
] = STATUS_REDUNDANT
;
111 ineq
[k
] = status_in(bmap_i
->ineq
[k
], tab_j
);
112 if (ineq
[k
] == STATUS_ERROR
)
114 if (ineq
[k
] == STATUS_SEPARATE
)
124 static int any(int *con
, unsigned len
, int status
)
128 for (i
= 0; i
< len
; ++i
)
129 if (con
[i
] == status
)
134 /* Return the first position of "status" in the list "con" of length "len".
135 * Return -1 if there is no such entry.
137 static int find(int *con
, unsigned len
, int status
)
141 for (i
= 0; i
< len
; ++i
)
142 if (con
[i
] == status
)
147 static int count(int *con
, unsigned len
, int status
)
152 for (i
= 0; i
< len
; ++i
)
153 if (con
[i
] == status
)
158 static int all(int *con
, unsigned len
, int status
)
162 for (i
= 0; i
< len
; ++i
) {
163 if (con
[i
] == STATUS_REDUNDANT
)
165 if (con
[i
] != status
)
171 /* Internal information associated to a basic map in a map
172 * that is to be coalesced by isl_map_coalesce.
174 * "bmap" is the basic map itself (or NULL if "removed" is set)
175 * "tab" is the corresponding tableau (or NULL if "removed" is set)
176 * "hull_hash" identifies the affine space in which "bmap" lives.
177 * "removed" is set if this basic map has been removed from the map
178 * "simplify" is set if this basic map may have some unknown integer
179 * divisions that were not present in the input basic maps. The basic
180 * map should then be simplified such that we may be able to find
181 * a definition among the constraints.
183 * "eq" and "ineq" are only set if we are currently trying to coalesce
184 * this basic map with another basic map, in which case they represent
185 * the position of the inequalities of this basic map with respect to
186 * the other basic map. The number of elements in the "eq" array
187 * is twice the number of equalities in the "bmap", corresponding
188 * to the two inequalities that make up each equality.
190 struct isl_coalesce_info
{
200 /* Are all non-redundant constraints of the basic map represented by "info"
201 * either valid or cut constraints with respect to the other basic map?
203 static int all_valid_or_cut(struct isl_coalesce_info
*info
)
207 for (i
= 0; i
< 2 * info
->bmap
->n_eq
; ++i
) {
208 if (info
->eq
[i
] == STATUS_REDUNDANT
)
210 if (info
->eq
[i
] == STATUS_VALID
)
212 if (info
->eq
[i
] == STATUS_CUT
)
217 for (i
= 0; i
< info
->bmap
->n_ineq
; ++i
) {
218 if (info
->ineq
[i
] == STATUS_REDUNDANT
)
220 if (info
->ineq
[i
] == STATUS_VALID
)
222 if (info
->ineq
[i
] == STATUS_CUT
)
230 /* Compute the hash of the (apparent) affine hull of info->bmap (with
231 * the existentially quantified variables removed) and store it
234 static int coalesce_info_set_hull_hash(struct isl_coalesce_info
*info
)
239 hull
= isl_basic_map_copy(info
->bmap
);
240 hull
= isl_basic_map_plain_affine_hull(hull
);
241 n_div
= isl_basic_map_dim(hull
, isl_dim_div
);
242 hull
= isl_basic_map_drop_constraints_involving_dims(hull
,
243 isl_dim_div
, 0, n_div
);
244 info
->hull_hash
= isl_basic_map_get_hash(hull
);
245 isl_basic_map_free(hull
);
247 return hull
? 0 : -1;
250 /* Free all the allocated memory in an array
251 * of "n" isl_coalesce_info elements.
253 static void clear_coalesce_info(int n
, struct isl_coalesce_info
*info
)
260 for (i
= 0; i
< n
; ++i
) {
261 isl_basic_map_free(info
[i
].bmap
);
262 isl_tab_free(info
[i
].tab
);
268 /* Drop the basic map represented by "info".
269 * That is, clear the memory associated to the entry and
270 * mark it as having been removed.
272 static void drop(struct isl_coalesce_info
*info
)
274 info
->bmap
= isl_basic_map_free(info
->bmap
);
275 isl_tab_free(info
->tab
);
280 /* Exchange the information in "info1" with that in "info2".
282 static void exchange(struct isl_coalesce_info
*info1
,
283 struct isl_coalesce_info
*info2
)
285 struct isl_coalesce_info info
;
292 /* This type represents the kind of change that has been performed
293 * while trying to coalesce two basic maps.
295 * isl_change_none: nothing was changed
296 * isl_change_drop_first: the first basic map was removed
297 * isl_change_drop_second: the second basic map was removed
298 * isl_change_fuse: the two basic maps were replaced by a new basic map.
301 isl_change_error
= -1,
303 isl_change_drop_first
,
304 isl_change_drop_second
,
308 /* Update "change" based on an interchange of the first and the second
309 * basic map. That is, interchange isl_change_drop_first and
310 * isl_change_drop_second.
312 static enum isl_change
invert_change(enum isl_change change
)
315 case isl_change_error
:
316 return isl_change_error
;
317 case isl_change_none
:
318 return isl_change_none
;
319 case isl_change_drop_first
:
320 return isl_change_drop_second
;
321 case isl_change_drop_second
:
322 return isl_change_drop_first
;
323 case isl_change_fuse
:
324 return isl_change_fuse
;
327 return isl_change_error
;
330 /* Add the valid constraints of the basic map represented by "info"
331 * to "bmap". "len" is the size of the constraints.
332 * If only one of the pair of inequalities that make up an equality
333 * is valid, then add that inequality.
335 static __isl_give isl_basic_map
*add_valid_constraints(
336 __isl_take isl_basic_map
*bmap
, struct isl_coalesce_info
*info
,
344 for (k
= 0; k
< info
->bmap
->n_eq
; ++k
) {
345 if (info
->eq
[2 * k
] == STATUS_VALID
&&
346 info
->eq
[2 * k
+ 1] == STATUS_VALID
) {
347 l
= isl_basic_map_alloc_equality(bmap
);
349 return isl_basic_map_free(bmap
);
350 isl_seq_cpy(bmap
->eq
[l
], info
->bmap
->eq
[k
], len
);
351 } else if (info
->eq
[2 * k
] == STATUS_VALID
) {
352 l
= isl_basic_map_alloc_inequality(bmap
);
354 return isl_basic_map_free(bmap
);
355 isl_seq_neg(bmap
->ineq
[l
], info
->bmap
->eq
[k
], len
);
356 } else if (info
->eq
[2 * k
+ 1] == STATUS_VALID
) {
357 l
= isl_basic_map_alloc_inequality(bmap
);
359 return isl_basic_map_free(bmap
);
360 isl_seq_cpy(bmap
->ineq
[l
], info
->bmap
->eq
[k
], len
);
364 for (k
= 0; k
< info
->bmap
->n_ineq
; ++k
) {
365 if (info
->ineq
[k
] != STATUS_VALID
)
367 l
= isl_basic_map_alloc_inequality(bmap
);
369 return isl_basic_map_free(bmap
);
370 isl_seq_cpy(bmap
->ineq
[l
], info
->bmap
->ineq
[k
], len
);
376 /* Is "bmap" defined by a number of (non-redundant) constraints that
377 * is greater than the number of constraints of basic maps i and j combined?
378 * Equalities are counted as two inequalities.
380 static int number_of_constraints_increases(int i
, int j
,
381 struct isl_coalesce_info
*info
,
382 __isl_keep isl_basic_map
*bmap
, struct isl_tab
*tab
)
386 n_old
= 2 * info
[i
].bmap
->n_eq
+ info
[i
].bmap
->n_ineq
;
387 n_old
+= 2 * info
[j
].bmap
->n_eq
+ info
[j
].bmap
->n_ineq
;
389 n_new
= 2 * bmap
->n_eq
;
390 for (k
= 0; k
< bmap
->n_ineq
; ++k
)
391 if (!isl_tab_is_redundant(tab
, bmap
->n_eq
+ k
))
394 return n_new
> n_old
;
397 /* Replace the pair of basic maps i and j by the basic map bounded
398 * by the valid constraints in both basic maps and the constraints
399 * in extra (if not NULL).
400 * Place the fused basic map in the position that is the smallest of i and j.
402 * If "detect_equalities" is set, then look for equalities encoded
403 * as pairs of inequalities.
404 * If "check_number" is set, then the original basic maps are only
405 * replaced if the total number of constraints does not increase.
406 * While the number of integer divisions in the two basic maps
407 * is assumed to be the same, the actual definitions may be different.
408 * We only copy the definition from one of the basic map if it is
409 * the same as that of the other basic map. Otherwise, we mark
410 * the integer division as unknown and simplify the basic map
411 * in an attempt to recover the integer division definition.
413 static enum isl_change
fuse(int i
, int j
, struct isl_coalesce_info
*info
,
414 __isl_keep isl_mat
*extra
, int detect_equalities
, int check_number
)
417 struct isl_basic_map
*fused
= NULL
;
418 struct isl_tab
*fused_tab
= NULL
;
419 unsigned total
= isl_basic_map_total_dim(info
[i
].bmap
);
420 unsigned extra_rows
= extra
? extra
->n_row
: 0;
421 unsigned n_eq
, n_ineq
;
425 return fuse(j
, i
, info
, extra
, detect_equalities
, check_number
);
427 n_eq
= info
[i
].bmap
->n_eq
+ info
[j
].bmap
->n_eq
;
428 n_ineq
= info
[i
].bmap
->n_ineq
+ info
[j
].bmap
->n_ineq
;
429 fused
= isl_basic_map_alloc_space(isl_space_copy(info
[i
].bmap
->dim
),
430 info
[i
].bmap
->n_div
, n_eq
, n_eq
+ n_ineq
+ extra_rows
);
431 fused
= add_valid_constraints(fused
, &info
[i
], 1 + total
);
432 fused
= add_valid_constraints(fused
, &info
[j
], 1 + total
);
435 if (ISL_F_ISSET(info
[i
].bmap
, ISL_BASIC_MAP_RATIONAL
) &&
436 ISL_F_ISSET(info
[j
].bmap
, ISL_BASIC_MAP_RATIONAL
))
437 ISL_F_SET(fused
, ISL_BASIC_MAP_RATIONAL
);
439 for (k
= 0; k
< info
[i
].bmap
->n_div
; ++k
) {
440 int l
= isl_basic_map_alloc_div(fused
);
443 if (isl_seq_eq(info
[i
].bmap
->div
[k
], info
[j
].bmap
->div
[k
],
445 isl_seq_cpy(fused
->div
[l
], info
[i
].bmap
->div
[k
],
448 isl_int_set_si(fused
->div
[l
][0], 0);
453 for (k
= 0; k
< extra_rows
; ++k
) {
454 l
= isl_basic_map_alloc_inequality(fused
);
457 isl_seq_cpy(fused
->ineq
[l
], extra
->row
[k
], 1 + total
);
460 if (detect_equalities
)
461 fused
= isl_basic_map_detect_inequality_pairs(fused
, NULL
);
462 fused
= isl_basic_map_gauss(fused
, NULL
);
463 if (simplify
|| info
[j
].simplify
) {
464 fused
= isl_basic_map_simplify(fused
);
465 info
[i
].simplify
= 0;
467 fused
= isl_basic_map_finalize(fused
);
469 fused_tab
= isl_tab_from_basic_map(fused
, 0);
470 if (isl_tab_detect_redundant(fused_tab
) < 0)
474 number_of_constraints_increases(i
, j
, info
, fused
, fused_tab
)) {
475 isl_tab_free(fused_tab
);
476 isl_basic_map_free(fused
);
477 return isl_change_none
;
480 isl_basic_map_free(info
[i
].bmap
);
481 info
[i
].bmap
= fused
;
482 isl_tab_free(info
[i
].tab
);
483 info
[i
].tab
= fused_tab
;
486 return isl_change_fuse
;
488 isl_tab_free(fused_tab
);
489 isl_basic_map_free(fused
);
490 return isl_change_error
;
493 /* Given a pair of basic maps i and j such that all constraints are either
494 * "valid" or "cut", check if the facets corresponding to the "cut"
495 * constraints of i lie entirely within basic map j.
496 * If so, replace the pair by the basic map consisting of the valid
497 * constraints in both basic maps.
498 * Checking whether the facet lies entirely within basic map j
499 * is performed by checking whether the constraints of basic map j
500 * are valid for the facet. These tests are performed on a rational
501 * tableau to avoid the theoretical possibility that a constraint
502 * that was considered to be a cut constraint for the entire basic map i
503 * happens to be considered to be a valid constraint for the facet,
504 * even though it cuts off the same rational points.
506 * To see that we are not introducing any extra points, call the
507 * two basic maps A and B and the resulting map U and let x
508 * be an element of U \setminus ( A \cup B ).
509 * A line connecting x with an element of A \cup B meets a facet F
510 * of either A or B. Assume it is a facet of B and let c_1 be
511 * the corresponding facet constraint. We have c_1(x) < 0 and
512 * so c_1 is a cut constraint. This implies that there is some
513 * (possibly rational) point x' satisfying the constraints of A
514 * and the opposite of c_1 as otherwise c_1 would have been marked
515 * valid for A. The line connecting x and x' meets a facet of A
516 * in a (possibly rational) point that also violates c_1, but this
517 * is impossible since all cut constraints of B are valid for all
519 * In case F is a facet of A rather than B, then we can apply the
520 * above reasoning to find a facet of B separating x from A \cup B first.
522 static enum isl_change
check_facets(int i
, int j
,
523 struct isl_coalesce_info
*info
)
526 struct isl_tab_undo
*snap
, *snap2
;
527 unsigned n_eq
= info
[i
].bmap
->n_eq
;
529 snap
= isl_tab_snap(info
[i
].tab
);
530 if (isl_tab_mark_rational(info
[i
].tab
) < 0)
531 return isl_change_error
;
532 snap2
= isl_tab_snap(info
[i
].tab
);
534 for (k
= 0; k
< info
[i
].bmap
->n_ineq
; ++k
) {
535 if (info
[i
].ineq
[k
] != STATUS_CUT
)
537 if (isl_tab_select_facet(info
[i
].tab
, n_eq
+ k
) < 0)
538 return isl_change_error
;
539 for (l
= 0; l
< info
[j
].bmap
->n_ineq
; ++l
) {
541 if (info
[j
].ineq
[l
] != STATUS_CUT
)
543 stat
= status_in(info
[j
].bmap
->ineq
[l
], info
[i
].tab
);
545 return isl_change_error
;
546 if (stat
!= STATUS_VALID
)
549 if (isl_tab_rollback(info
[i
].tab
, snap2
) < 0)
550 return isl_change_error
;
551 if (l
< info
[j
].bmap
->n_ineq
)
555 if (k
< info
[i
].bmap
->n_ineq
) {
556 if (isl_tab_rollback(info
[i
].tab
, snap
) < 0)
557 return isl_change_error
;
558 return isl_change_none
;
560 return fuse(i
, j
, info
, NULL
, 0, 0);
563 /* Check if info->bmap contains the basic map represented
564 * by the tableau "tab".
565 * For each equality, we check both the constraint itself
566 * (as an inequality) and its negation. Make sure the
567 * equality is returned to its original state before returning.
569 static int contains(struct isl_coalesce_info
*info
, struct isl_tab
*tab
)
573 isl_basic_map
*bmap
= info
->bmap
;
575 dim
= isl_basic_map_total_dim(bmap
);
576 for (k
= 0; k
< bmap
->n_eq
; ++k
) {
578 isl_seq_neg(bmap
->eq
[k
], bmap
->eq
[k
], 1 + dim
);
579 stat
= status_in(bmap
->eq
[k
], tab
);
580 isl_seq_neg(bmap
->eq
[k
], bmap
->eq
[k
], 1 + dim
);
583 if (stat
!= STATUS_VALID
)
585 stat
= status_in(bmap
->eq
[k
], tab
);
588 if (stat
!= STATUS_VALID
)
592 for (k
= 0; k
< bmap
->n_ineq
; ++k
) {
594 if (info
->ineq
[k
] == STATUS_REDUNDANT
)
596 stat
= status_in(bmap
->ineq
[k
], tab
);
599 if (stat
!= STATUS_VALID
)
605 /* Basic map "i" has an inequality (say "k") that is adjacent
606 * to some inequality of basic map "j". All the other inequalities
608 * Check if basic map "j" forms an extension of basic map "i".
610 * Note that this function is only called if some of the equalities or
611 * inequalities of basic map "j" do cut basic map "i". The function is
612 * correct even if there are no such cut constraints, but in that case
613 * the additional checks performed by this function are overkill.
615 * In particular, we replace constraint k, say f >= 0, by constraint
616 * f <= -1, add the inequalities of "j" that are valid for "i"
617 * and check if the result is a subset of basic map "j".
618 * If so, then we know that this result is exactly equal to basic map "j"
619 * since all its constraints are valid for basic map "j".
620 * By combining the valid constraints of "i" (all equalities and all
621 * inequalities except "k") and the valid constraints of "j" we therefore
622 * obtain a basic map that is equal to their union.
623 * In this case, there is no need to perform a rollback of the tableau
624 * since it is going to be destroyed in fuse().
630 * |_______| _ |_________\
642 static enum isl_change
is_adj_ineq_extension(int i
, int j
,
643 struct isl_coalesce_info
*info
)
646 struct isl_tab_undo
*snap
;
647 unsigned n_eq
= info
[i
].bmap
->n_eq
;
648 unsigned total
= isl_basic_map_total_dim(info
[i
].bmap
);
652 if (isl_tab_extend_cons(info
[i
].tab
, 1 + info
[j
].bmap
->n_ineq
) < 0)
653 return isl_change_error
;
655 k
= find(info
[i
].ineq
, info
[i
].bmap
->n_ineq
, STATUS_ADJ_INEQ
);
657 isl_die(isl_basic_map_get_ctx(info
[i
].bmap
), isl_error_internal
,
658 "info[i].ineq should have exactly one STATUS_ADJ_INEQ",
659 return isl_change_error
);
661 snap
= isl_tab_snap(info
[i
].tab
);
663 if (isl_tab_unrestrict(info
[i
].tab
, n_eq
+ k
) < 0)
664 return isl_change_error
;
666 isl_seq_neg(info
[i
].bmap
->ineq
[k
], info
[i
].bmap
->ineq
[k
], 1 + total
);
667 isl_int_sub_ui(info
[i
].bmap
->ineq
[k
][0], info
[i
].bmap
->ineq
[k
][0], 1);
668 r
= isl_tab_add_ineq(info
[i
].tab
, info
[i
].bmap
->ineq
[k
]);
669 isl_seq_neg(info
[i
].bmap
->ineq
[k
], info
[i
].bmap
->ineq
[k
], 1 + total
);
670 isl_int_sub_ui(info
[i
].bmap
->ineq
[k
][0], info
[i
].bmap
->ineq
[k
][0], 1);
672 return isl_change_error
;
674 for (k
= 0; k
< info
[j
].bmap
->n_ineq
; ++k
) {
675 if (info
[j
].ineq
[k
] != STATUS_VALID
)
677 if (isl_tab_add_ineq(info
[i
].tab
, info
[j
].bmap
->ineq
[k
]) < 0)
678 return isl_change_error
;
681 super
= contains(&info
[j
], info
[i
].tab
);
683 return isl_change_error
;
685 return fuse(i
, j
, info
, NULL
, 0, 0);
687 if (isl_tab_rollback(info
[i
].tab
, snap
) < 0)
688 return isl_change_error
;
690 return isl_change_none
;
694 /* Both basic maps have at least one inequality with and adjacent
695 * (but opposite) inequality in the other basic map.
696 * Check that there are no cut constraints and that there is only
697 * a single pair of adjacent inequalities.
698 * If so, we can replace the pair by a single basic map described
699 * by all but the pair of adjacent inequalities.
700 * Any additional points introduced lie strictly between the two
701 * adjacent hyperplanes and can therefore be integral.
710 * The test for a single pair of adjancent inequalities is important
711 * for avoiding the combination of two basic maps like the following
721 * If there are some cut constraints on one side, then we may
722 * still be able to fuse the two basic maps, but we need to perform
723 * some additional checks in is_adj_ineq_extension.
725 static enum isl_change
check_adj_ineq(int i
, int j
,
726 struct isl_coalesce_info
*info
)
728 int count_i
, count_j
;
731 count_i
= count(info
[i
].ineq
, info
[i
].bmap
->n_ineq
, STATUS_ADJ_INEQ
);
732 count_j
= count(info
[j
].ineq
, info
[j
].bmap
->n_ineq
, STATUS_ADJ_INEQ
);
734 if (count_i
!= 1 && count_j
!= 1)
735 return isl_change_none
;
737 cut_i
= any(info
[i
].eq
, 2 * info
[i
].bmap
->n_eq
, STATUS_CUT
) ||
738 any(info
[i
].ineq
, info
[i
].bmap
->n_ineq
, STATUS_CUT
);
739 cut_j
= any(info
[j
].eq
, 2 * info
[j
].bmap
->n_eq
, STATUS_CUT
) ||
740 any(info
[j
].ineq
, info
[j
].bmap
->n_ineq
, STATUS_CUT
);
742 if (!cut_i
&& !cut_j
&& count_i
== 1 && count_j
== 1)
743 return fuse(i
, j
, info
, NULL
, 0, 0);
745 if (count_i
== 1 && !cut_i
)
746 return is_adj_ineq_extension(i
, j
, info
);
748 if (count_j
== 1 && !cut_j
)
749 return is_adj_ineq_extension(j
, i
, info
);
751 return isl_change_none
;
754 /* Given an affine transformation matrix "T", does row "row" represent
755 * anything other than a unit vector (possibly shifted by a constant)
756 * that is not involved in any of the other rows?
758 * That is, if a constraint involves the variable corresponding to
759 * the row, then could its preimage by "T" have any coefficients
760 * that are different from those in the original constraint?
762 static int not_unique_unit_row(__isl_keep isl_mat
*T
, int row
)
765 int len
= T
->n_col
- 1;
767 i
= isl_seq_first_non_zero(T
->row
[row
] + 1, len
);
770 if (!isl_int_is_one(T
->row
[row
][1 + i
]) &&
771 !isl_int_is_negone(T
->row
[row
][1 + i
]))
774 j
= isl_seq_first_non_zero(T
->row
[row
] + 1 + i
+ 1, len
- (i
+ 1));
778 for (j
= 1; j
< T
->n_row
; ++j
) {
781 if (!isl_int_is_zero(T
->row
[j
][1 + i
]))
788 /* Does inequality constraint "ineq" of "bmap" involve any of
789 * the variables marked in "affected"?
790 * "total" is the total number of variables, i.e., the number
791 * of entries in "affected".
793 static int is_affected(__isl_keep isl_basic_map
*bmap
, int ineq
, int *affected
,
798 for (i
= 0; i
< total
; ++i
) {
801 if (!isl_int_is_zero(bmap
->ineq
[ineq
][1 + i
]))
808 /* Given the compressed version of inequality constraint "ineq"
809 * of info->bmap in "v", check if the constraint can be tightened,
810 * where the compression is based on an equality constraint valid
812 * If so, add the tightened version of the inequality constraint
813 * to info->tab. "v" may be modified by this function.
815 * That is, if the compressed constraint is of the form
819 * with 0 < c < m, then it is equivalent to
823 * This means that c can also be subtracted from the original,
824 * uncompressed constraint without affecting the integer points
825 * in info->tab. Add this tightened constraint as an extra row
826 * to info->tab to make this information explicitly available.
828 static __isl_give isl_vec
*try_tightening(struct isl_coalesce_info
*info
,
829 int ineq
, __isl_take isl_vec
*v
)
837 ctx
= isl_vec_get_ctx(v
);
838 isl_seq_gcd(v
->el
+ 1, v
->size
- 1, &ctx
->normalize_gcd
);
839 if (isl_int_is_zero(ctx
->normalize_gcd
) ||
840 isl_int_is_one(ctx
->normalize_gcd
)) {
848 isl_int_fdiv_r(v
->el
[0], v
->el
[0], ctx
->normalize_gcd
);
849 if (isl_int_is_zero(v
->el
[0]))
852 if (isl_tab_extend_cons(info
->tab
, 1) < 0)
853 return isl_vec_free(v
);
855 isl_int_sub(info
->bmap
->ineq
[ineq
][0],
856 info
->bmap
->ineq
[ineq
][0], v
->el
[0]);
857 r
= isl_tab_add_ineq(info
->tab
, info
->bmap
->ineq
[ineq
]);
858 isl_int_add(info
->bmap
->ineq
[ineq
][0],
859 info
->bmap
->ineq
[ineq
][0], v
->el
[0]);
862 return isl_vec_free(v
);
867 /* Tighten the (non-redundant) constraints on the facet represented
869 * In particular, on input, info->tab represents the result
870 * of replacing constraint k of info->bmap, i.e., f_k >= 0,
871 * by the adjacent equality, i.e., f_k + 1 = 0.
873 * Compute a variable compression from the equality constraint f_k + 1 = 0
874 * and use it to tighten the other constraints of info->bmap,
875 * updating info->tab (and leaving info->bmap untouched).
876 * The compression handles essentially two cases, one where a variable
877 * is assigned a fixed value and can therefore be eliminated, and one
878 * where one variable is a shifted multiple of some other variable and
879 * can therefore be replaced by that multiple.
880 * Gaussian elimination would also work for the first case, but for
881 * the second case, the effectiveness would depend on the order
883 * After compression, some of the constraints may have coefficients
884 * with a common divisor. If this divisor does not divide the constant
885 * term, then the constraint can be tightened.
886 * The tightening is performed on the tableau info->tab by introducing
887 * extra (temporary) constraints.
889 * Only constraints that are possibly affected by the compression are
890 * considered. In particular, if the constraint only involves variables
891 * that are directly mapped to a distinct set of other variables, then
892 * no common divisor can be introduced and no tightening can occur.
894 * It is important to only consider the non-redundant constraints
895 * since the facet constraint has been relaxed prior to the call
896 * to this function, meaning that the constraints that were redundant
897 * prior to the relaxation may no longer be redundant.
898 * These constraints will be ignored in the fused result, so
899 * the fusion detection should not exploit them.
901 static isl_stat
tighten_on_relaxed_facet(struct isl_coalesce_info
*info
,
911 ctx
= isl_basic_map_get_ctx(info
->bmap
);
912 total
= isl_basic_map_total_dim(info
->bmap
);
913 isl_int_add_ui(info
->bmap
->ineq
[k
][0], info
->bmap
->ineq
[k
][0], 1);
914 T
= isl_mat_sub_alloc6(ctx
, info
->bmap
->ineq
, k
, 1, 0, 1 + total
);
915 T
= isl_mat_variable_compression(T
, NULL
);
916 isl_int_sub_ui(info
->bmap
->ineq
[k
][0], info
->bmap
->ineq
[k
][0], 1);
918 return isl_stat_error
;
924 affected
= isl_alloc_array(ctx
, int, total
);
928 for (i
= 0; i
< total
; ++i
)
929 affected
[i
] = not_unique_unit_row(T
, 1 + i
);
931 for (i
= 0; i
< info
->bmap
->n_ineq
; ++i
) {
934 if (info
->ineq
[i
] == STATUS_REDUNDANT
)
936 if (!is_affected(info
->bmap
, i
, affected
, total
))
938 v
= isl_vec_alloc(ctx
, 1 + total
);
941 isl_seq_cpy(v
->el
, info
->bmap
->ineq
[i
], 1 + total
);
942 v
= isl_vec_mat_product(v
, isl_mat_copy(T
));
943 v
= try_tightening(info
, i
, v
);
955 return isl_stat_error
;
958 /* Basic map "i" has an inequality "k" that is adjacent to some equality
959 * of basic map "j". All the other inequalities are valid for "j".
960 * Check if basic map "j" forms an extension of basic map "i".
962 * In particular, we relax constraint "k", compute the corresponding
963 * facet and check whether it is included in the other basic map.
964 * Before testing for inclusion, the constraints on the facet
965 * are tightened to increase the chance of an inclusion being detected.
966 * If the facet is included, we know that relaxing the constraint extends
967 * the basic map with exactly the other basic map (we already know that this
968 * other basic map is included in the extension, because there
969 * were no "cut" inequalities in "i") and we can replace the
970 * two basic maps by this extension.
971 * Each integer division that does not have exactly the same
972 * definition in "i" and "j" is marked unknown and the basic map
973 * is scheduled to be simplified in an attempt to recover
974 * the integer division definition.
975 * Place this extension in the position that is the smallest of i and j.
983 static enum isl_change
is_adj_eq_extension(int i
, int j
, int k
,
984 struct isl_coalesce_info
*info
)
986 int change
= isl_change_none
;
988 struct isl_tab_undo
*snap
, *snap2
;
989 unsigned n_eq
= info
[i
].bmap
->n_eq
;
991 if (isl_tab_is_equality(info
[i
].tab
, n_eq
+ k
))
992 return isl_change_none
;
994 snap
= isl_tab_snap(info
[i
].tab
);
995 if (isl_tab_relax(info
[i
].tab
, n_eq
+ k
) < 0)
996 return isl_change_error
;
997 snap2
= isl_tab_snap(info
[i
].tab
);
998 if (isl_tab_select_facet(info
[i
].tab
, n_eq
+ k
) < 0)
999 return isl_change_error
;
1000 if (tighten_on_relaxed_facet(&info
[i
], k
) < 0)
1001 return isl_change_error
;
1002 super
= contains(&info
[j
], info
[i
].tab
);
1004 return isl_change_error
;
1009 if (isl_tab_rollback(info
[i
].tab
, snap2
) < 0)
1010 return isl_change_error
;
1011 info
[i
].bmap
= isl_basic_map_cow(info
[i
].bmap
);
1013 return isl_change_error
;
1014 total
= isl_basic_map_total_dim(info
[i
].bmap
);
1015 for (l
= 0; l
< info
[i
].bmap
->n_div
; ++l
)
1016 if (!isl_seq_eq(info
[i
].bmap
->div
[l
],
1017 info
[j
].bmap
->div
[l
], 1 + 1 + total
)) {
1018 isl_int_set_si(info
[i
].bmap
->div
[l
][0], 0);
1019 info
[i
].simplify
= 1;
1021 isl_int_add_ui(info
[i
].bmap
->ineq
[k
][0],
1022 info
[i
].bmap
->ineq
[k
][0], 1);
1023 ISL_F_SET(info
[i
].bmap
, ISL_BASIC_MAP_FINAL
);
1026 exchange(&info
[i
], &info
[j
]);
1027 change
= isl_change_fuse
;
1029 if (isl_tab_rollback(info
[i
].tab
, snap
) < 0)
1030 return isl_change_error
;
1035 /* Data structure that keeps track of the wrapping constraints
1036 * and of information to bound the coefficients of those constraints.
1038 * bound is set if we want to apply a bound on the coefficients
1039 * mat contains the wrapping constraints
1040 * max is the bound on the coefficients (if bound is set)
1048 /* Update wraps->max to be greater than or equal to the coefficients
1049 * in the equalities and inequalities of info->bmap that can be removed
1050 * if we end up applying wrapping.
1052 static void wraps_update_max(struct isl_wraps
*wraps
,
1053 struct isl_coalesce_info
*info
)
1057 unsigned total
= isl_basic_map_total_dim(info
->bmap
);
1059 isl_int_init(max_k
);
1061 for (k
= 0; k
< info
->bmap
->n_eq
; ++k
) {
1062 if (info
->eq
[2 * k
] == STATUS_VALID
&&
1063 info
->eq
[2 * k
+ 1] == STATUS_VALID
)
1065 isl_seq_abs_max(info
->bmap
->eq
[k
] + 1, total
, &max_k
);
1066 if (isl_int_abs_gt(max_k
, wraps
->max
))
1067 isl_int_set(wraps
->max
, max_k
);
1070 for (k
= 0; k
< info
->bmap
->n_ineq
; ++k
) {
1071 if (info
->ineq
[k
] == STATUS_VALID
||
1072 info
->ineq
[k
] == STATUS_REDUNDANT
)
1074 isl_seq_abs_max(info
->bmap
->ineq
[k
] + 1, total
, &max_k
);
1075 if (isl_int_abs_gt(max_k
, wraps
->max
))
1076 isl_int_set(wraps
->max
, max_k
);
1079 isl_int_clear(max_k
);
1082 /* Initialize the isl_wraps data structure.
1083 * If we want to bound the coefficients of the wrapping constraints,
1084 * we set wraps->max to the largest coefficient
1085 * in the equalities and inequalities that can be removed if we end up
1086 * applying wrapping.
1088 static void wraps_init(struct isl_wraps
*wraps
, __isl_take isl_mat
*mat
,
1089 struct isl_coalesce_info
*info
, int i
, int j
)
1097 ctx
= isl_mat_get_ctx(mat
);
1098 wraps
->bound
= isl_options_get_coalesce_bounded_wrapping(ctx
);
1101 isl_int_init(wraps
->max
);
1102 isl_int_set_si(wraps
->max
, 0);
1103 wraps_update_max(wraps
, &info
[i
]);
1104 wraps_update_max(wraps
, &info
[j
]);
1107 /* Free the contents of the isl_wraps data structure.
1109 static void wraps_free(struct isl_wraps
*wraps
)
1111 isl_mat_free(wraps
->mat
);
1113 isl_int_clear(wraps
->max
);
1116 /* Is the wrapping constraint in row "row" allowed?
1118 * If wraps->bound is set, we check that none of the coefficients
1119 * is greater than wraps->max.
1121 static int allow_wrap(struct isl_wraps
*wraps
, int row
)
1128 for (i
= 1; i
< wraps
->mat
->n_col
; ++i
)
1129 if (isl_int_abs_gt(wraps
->mat
->row
[row
][i
], wraps
->max
))
1135 /* Wrap "ineq" (or its opposite if "negate" is set) around "bound"
1136 * to include "set" and add the result in position "w" of "wraps".
1137 * "len" is the total number of coefficients in "bound" and "ineq".
1138 * Return 1 on success, 0 on failure and -1 on error.
1139 * Wrapping can fail if the result of wrapping is equal to "bound"
1140 * or if we want to bound the sizes of the coefficients and
1141 * the wrapped constraint does not satisfy this bound.
1143 static int add_wrap(struct isl_wraps
*wraps
, int w
, isl_int
*bound
,
1144 isl_int
*ineq
, unsigned len
, __isl_keep isl_set
*set
, int negate
)
1146 isl_seq_cpy(wraps
->mat
->row
[w
], bound
, len
);
1148 isl_seq_neg(wraps
->mat
->row
[w
+ 1], ineq
, len
);
1149 ineq
= wraps
->mat
->row
[w
+ 1];
1151 if (!isl_set_wrap_facet(set
, wraps
->mat
->row
[w
], ineq
))
1153 if (isl_seq_eq(wraps
->mat
->row
[w
], bound
, len
))
1155 if (!allow_wrap(wraps
, w
))
1160 /* For each constraint in info->bmap that is not redundant (as determined
1161 * by info->tab) and that is not a valid constraint for the other basic map,
1162 * wrap the constraint around "bound" such that it includes the whole
1163 * set "set" and append the resulting constraint to "wraps".
1164 * Note that the constraints that are valid for the other basic map
1165 * will be added to the combined basic map by default, so there is
1166 * no need to wrap them.
1167 * The caller wrap_in_facets even relies on this function not wrapping
1168 * any constraints that are already valid.
1169 * "wraps" is assumed to have been pre-allocated to the appropriate size.
1170 * wraps->n_row is the number of actual wrapped constraints that have
1172 * If any of the wrapping problems results in a constraint that is
1173 * identical to "bound", then this means that "set" is unbounded in such
1174 * way that no wrapping is possible. If this happens then wraps->n_row
1176 * Similarly, if we want to bound the coefficients of the wrapping
1177 * constraints and a newly added wrapping constraint does not
1178 * satisfy the bound, then wraps->n_row is also reset to zero.
1180 static int add_wraps(struct isl_wraps
*wraps
, struct isl_coalesce_info
*info
,
1181 isl_int
*bound
, __isl_keep isl_set
*set
)
1186 isl_basic_map
*bmap
= info
->bmap
;
1187 unsigned len
= 1 + isl_basic_map_total_dim(bmap
);
1189 w
= wraps
->mat
->n_row
;
1191 for (l
= 0; l
< bmap
->n_ineq
; ++l
) {
1192 if (info
->ineq
[l
] == STATUS_VALID
||
1193 info
->ineq
[l
] == STATUS_REDUNDANT
)
1195 if (isl_seq_is_neg(bound
, bmap
->ineq
[l
], len
))
1197 if (isl_seq_eq(bound
, bmap
->ineq
[l
], len
))
1199 if (isl_tab_is_redundant(info
->tab
, bmap
->n_eq
+ l
))
1202 added
= add_wrap(wraps
, w
, bound
, bmap
->ineq
[l
], len
, set
, 0);
1209 for (l
= 0; l
< bmap
->n_eq
; ++l
) {
1210 if (isl_seq_is_neg(bound
, bmap
->eq
[l
], len
))
1212 if (isl_seq_eq(bound
, bmap
->eq
[l
], len
))
1215 for (m
= 0; m
< 2; ++m
) {
1216 if (info
->eq
[2 * l
+ m
] == STATUS_VALID
)
1218 added
= add_wrap(wraps
, w
, bound
, bmap
->eq
[l
], len
,
1228 wraps
->mat
->n_row
= w
;
1231 wraps
->mat
->n_row
= 0;
1235 /* Check if the constraints in "wraps" from "first" until the last
1236 * are all valid for the basic set represented by "tab".
1237 * If not, wraps->n_row is set to zero.
1239 static int check_wraps(__isl_keep isl_mat
*wraps
, int first
,
1240 struct isl_tab
*tab
)
1244 for (i
= first
; i
< wraps
->n_row
; ++i
) {
1245 enum isl_ineq_type type
;
1246 type
= isl_tab_ineq_type(tab
, wraps
->row
[i
]);
1247 if (type
== isl_ineq_error
)
1249 if (type
== isl_ineq_redundant
)
1258 /* Return a set that corresponds to the non-redundant constraints
1259 * (as recorded in tab) of bmap.
1261 * It's important to remove the redundant constraints as some
1262 * of the other constraints may have been modified after the
1263 * constraints were marked redundant.
1264 * In particular, a constraint may have been relaxed.
1265 * Redundant constraints are ignored when a constraint is relaxed
1266 * and should therefore continue to be ignored ever after.
1267 * Otherwise, the relaxation might be thwarted by some of
1268 * these constraints.
1270 * Update the underlying set to ensure that the dimension doesn't change.
1271 * Otherwise the integer divisions could get dropped if the tab
1272 * turns out to be empty.
1274 static __isl_give isl_set
*set_from_updated_bmap(__isl_keep isl_basic_map
*bmap
,
1275 struct isl_tab
*tab
)
1277 isl_basic_set
*bset
;
1279 bmap
= isl_basic_map_copy(bmap
);
1280 bset
= isl_basic_map_underlying_set(bmap
);
1281 bset
= isl_basic_set_cow(bset
);
1282 bset
= isl_basic_set_update_from_tab(bset
, tab
);
1283 return isl_set_from_basic_set(bset
);
1286 /* Wrap the constraints of info->bmap that bound the facet defined
1287 * by inequality "k" around (the opposite of) this inequality to
1288 * include "set". "bound" may be used to store the negated inequality.
1289 * Since the wrapped constraints are not guaranteed to contain the whole
1290 * of info->bmap, we check them in check_wraps.
1291 * If any of the wrapped constraints turn out to be invalid, then
1292 * check_wraps will reset wrap->n_row to zero.
1294 static int add_wraps_around_facet(struct isl_wraps
*wraps
,
1295 struct isl_coalesce_info
*info
, int k
, isl_int
*bound
,
1296 __isl_keep isl_set
*set
)
1298 struct isl_tab_undo
*snap
;
1300 unsigned total
= isl_basic_map_total_dim(info
->bmap
);
1302 snap
= isl_tab_snap(info
->tab
);
1304 if (isl_tab_select_facet(info
->tab
, info
->bmap
->n_eq
+ k
) < 0)
1306 if (isl_tab_detect_redundant(info
->tab
) < 0)
1309 isl_seq_neg(bound
, info
->bmap
->ineq
[k
], 1 + total
);
1311 n
= wraps
->mat
->n_row
;
1312 if (add_wraps(wraps
, info
, bound
, set
) < 0)
1315 if (isl_tab_rollback(info
->tab
, snap
) < 0)
1317 if (check_wraps(wraps
->mat
, n
, info
->tab
) < 0)
1323 /* Given a basic set i with a constraint k that is adjacent to
1324 * basic set j, check if we can wrap
1325 * both the facet corresponding to k (if "wrap_facet" is set) and basic map j
1326 * (always) around their ridges to include the other set.
1327 * If so, replace the pair of basic sets by their union.
1329 * All constraints of i (except k) are assumed to be valid or
1330 * cut constraints for j.
1331 * Wrapping the cut constraints to include basic map j may result
1332 * in constraints that are no longer valid of basic map i
1333 * we have to check that the resulting wrapping constraints are valid for i.
1334 * If "wrap_facet" is not set, then all constraints of i (except k)
1335 * are assumed to be valid for j.
1344 static enum isl_change
can_wrap_in_facet(int i
, int j
, int k
,
1345 struct isl_coalesce_info
*info
, int wrap_facet
)
1347 enum isl_change change
= isl_change_none
;
1348 struct isl_wraps wraps
;
1351 struct isl_set
*set_i
= NULL
;
1352 struct isl_set
*set_j
= NULL
;
1353 struct isl_vec
*bound
= NULL
;
1354 unsigned total
= isl_basic_map_total_dim(info
[i
].bmap
);
1356 set_i
= set_from_updated_bmap(info
[i
].bmap
, info
[i
].tab
);
1357 set_j
= set_from_updated_bmap(info
[j
].bmap
, info
[j
].tab
);
1358 ctx
= isl_basic_map_get_ctx(info
[i
].bmap
);
1359 mat
= isl_mat_alloc(ctx
, 2 * (info
[i
].bmap
->n_eq
+ info
[j
].bmap
->n_eq
) +
1360 info
[i
].bmap
->n_ineq
+ info
[j
].bmap
->n_ineq
,
1362 wraps_init(&wraps
, mat
, info
, i
, j
);
1363 bound
= isl_vec_alloc(ctx
, 1 + total
);
1364 if (!set_i
|| !set_j
|| !wraps
.mat
|| !bound
)
1367 isl_seq_cpy(bound
->el
, info
[i
].bmap
->ineq
[k
], 1 + total
);
1368 isl_int_add_ui(bound
->el
[0], bound
->el
[0], 1);
1370 isl_seq_cpy(wraps
.mat
->row
[0], bound
->el
, 1 + total
);
1371 wraps
.mat
->n_row
= 1;
1373 if (add_wraps(&wraps
, &info
[j
], bound
->el
, set_i
) < 0)
1375 if (!wraps
.mat
->n_row
)
1379 if (add_wraps_around_facet(&wraps
, &info
[i
], k
,
1380 bound
->el
, set_j
) < 0)
1382 if (!wraps
.mat
->n_row
)
1386 change
= fuse(i
, j
, info
, wraps
.mat
, 0, 0);
1391 isl_set_free(set_i
);
1392 isl_set_free(set_j
);
1394 isl_vec_free(bound
);
1399 isl_vec_free(bound
);
1400 isl_set_free(set_i
);
1401 isl_set_free(set_j
);
1402 return isl_change_error
;
1405 /* Given a cut constraint t(x) >= 0 of basic map i, stored in row "w"
1406 * of wrap.mat, replace it by its relaxed version t(x) + 1 >= 0, and
1407 * add wrapping constraints to wrap.mat for all constraints
1408 * of basic map j that bound the part of basic map j that sticks out
1409 * of the cut constraint.
1410 * "set_i" is the underlying set of basic map i.
1411 * If any wrapping fails, then wraps->mat.n_row is reset to zero.
1413 * In particular, we first intersect basic map j with t(x) + 1 = 0.
1414 * If the result is empty, then t(x) >= 0 was actually a valid constraint
1415 * (with respect to the integer points), so we add t(x) >= 0 instead.
1416 * Otherwise, we wrap the constraints of basic map j that are not
1417 * redundant in this intersection and that are not already valid
1418 * for basic map i over basic map i.
1419 * Note that it is sufficient to wrap the constraints to include
1420 * basic map i, because we will only wrap the constraints that do
1421 * not include basic map i already. The wrapped constraint will
1422 * therefore be more relaxed compared to the original constraint.
1423 * Since the original constraint is valid for basic map j, so is
1424 * the wrapped constraint.
1426 static isl_stat
wrap_in_facet(struct isl_wraps
*wraps
, int w
,
1427 struct isl_coalesce_info
*info_j
, __isl_keep isl_set
*set_i
,
1428 struct isl_tab_undo
*snap
)
1430 isl_int_add_ui(wraps
->mat
->row
[w
][0], wraps
->mat
->row
[w
][0], 1);
1431 if (isl_tab_add_eq(info_j
->tab
, wraps
->mat
->row
[w
]) < 0)
1432 return isl_stat_error
;
1433 if (isl_tab_detect_redundant(info_j
->tab
) < 0)
1434 return isl_stat_error
;
1436 if (info_j
->tab
->empty
)
1437 isl_int_sub_ui(wraps
->mat
->row
[w
][0], wraps
->mat
->row
[w
][0], 1);
1438 else if (add_wraps(wraps
, info_j
, wraps
->mat
->row
[w
], set_i
) < 0)
1439 return isl_stat_error
;
1441 if (isl_tab_rollback(info_j
->tab
, snap
) < 0)
1442 return isl_stat_error
;
1447 /* Given a pair of basic maps i and j such that j sticks out
1448 * of i at n cut constraints, each time by at most one,
1449 * try to compute wrapping constraints and replace the two
1450 * basic maps by a single basic map.
1451 * The other constraints of i are assumed to be valid for j.
1452 * "set_i" is the underlying set of basic map i.
1453 * "wraps" has been initialized to be of the right size.
1455 * For each cut constraint t(x) >= 0 of i, we add the relaxed version
1456 * t(x) + 1 >= 0, along with wrapping constraints for all constraints
1457 * of basic map j that bound the part of basic map j that sticks out
1458 * of the cut constraint.
1460 * If any wrapping fails, i.e., if we cannot wrap to touch
1461 * the union, then we give up.
1462 * Otherwise, the pair of basic maps is replaced by their union.
1464 static enum isl_change
try_wrap_in_facets(int i
, int j
,
1465 struct isl_coalesce_info
*info
, struct isl_wraps
*wraps
,
1466 __isl_keep isl_set
*set_i
)
1470 struct isl_tab_undo
*snap
;
1472 total
= isl_basic_map_total_dim(info
[i
].bmap
);
1474 snap
= isl_tab_snap(info
[j
].tab
);
1476 wraps
->mat
->n_row
= 0;
1478 for (k
= 0; k
< info
[i
].bmap
->n_eq
; ++k
) {
1479 for (l
= 0; l
< 2; ++l
) {
1480 if (info
[i
].eq
[2 * k
+ l
] != STATUS_CUT
)
1482 w
= wraps
->mat
->n_row
++;
1484 isl_seq_neg(wraps
->mat
->row
[w
],
1485 info
[i
].bmap
->eq
[k
], 1 + total
);
1487 isl_seq_cpy(wraps
->mat
->row
[w
],
1488 info
[i
].bmap
->eq
[k
], 1 + total
);
1489 if (wrap_in_facet(wraps
, w
, &info
[j
], set_i
, snap
) < 0)
1490 return isl_change_error
;
1492 if (!wraps
->mat
->n_row
)
1493 return isl_change_none
;
1497 for (k
= 0; k
< info
[i
].bmap
->n_ineq
; ++k
) {
1498 if (info
[i
].ineq
[k
] != STATUS_CUT
)
1500 w
= wraps
->mat
->n_row
++;
1501 isl_seq_cpy(wraps
->mat
->row
[w
],
1502 info
[i
].bmap
->ineq
[k
], 1 + total
);
1503 if (wrap_in_facet(wraps
, w
, &info
[j
], set_i
, snap
) < 0)
1504 return isl_change_error
;
1506 if (!wraps
->mat
->n_row
)
1507 return isl_change_none
;
1510 return fuse(i
, j
, info
, wraps
->mat
, 0, 1);
1513 /* Given a pair of basic maps i and j such that j sticks out
1514 * of i at n cut constraints, each time by at most one,
1515 * try to compute wrapping constraints and replace the two
1516 * basic maps by a single basic map.
1517 * The other constraints of i are assumed to be valid for j.
1519 * The core computation is performed by try_wrap_in_facets.
1520 * This function simply extracts an underlying set representation
1521 * of basic map i and initializes the data structure for keeping
1522 * track of wrapping constraints.
1524 static enum isl_change
wrap_in_facets(int i
, int j
, int n
,
1525 struct isl_coalesce_info
*info
)
1527 enum isl_change change
= isl_change_none
;
1528 struct isl_wraps wraps
;
1531 isl_set
*set_i
= NULL
;
1532 unsigned total
= isl_basic_map_total_dim(info
[i
].bmap
);
1535 if (isl_tab_extend_cons(info
[j
].tab
, 1) < 0)
1536 return isl_change_error
;
1538 max_wrap
= 1 + 2 * info
[j
].bmap
->n_eq
+ info
[j
].bmap
->n_ineq
;
1541 set_i
= set_from_updated_bmap(info
[i
].bmap
, info
[i
].tab
);
1542 ctx
= isl_basic_map_get_ctx(info
[i
].bmap
);
1543 mat
= isl_mat_alloc(ctx
, max_wrap
, 1 + total
);
1544 wraps_init(&wraps
, mat
, info
, i
, j
);
1545 if (!set_i
|| !wraps
.mat
)
1548 change
= try_wrap_in_facets(i
, j
, info
, &wraps
, set_i
);
1551 isl_set_free(set_i
);
1556 isl_set_free(set_i
);
1557 return isl_change_error
;
1560 /* Return the effect of inequality "ineq" on the tableau "tab",
1561 * after relaxing the constant term of "ineq" by one.
1563 static enum isl_ineq_type
type_of_relaxed(struct isl_tab
*tab
, isl_int
*ineq
)
1565 enum isl_ineq_type type
;
1567 isl_int_add_ui(ineq
[0], ineq
[0], 1);
1568 type
= isl_tab_ineq_type(tab
, ineq
);
1569 isl_int_sub_ui(ineq
[0], ineq
[0], 1);
1574 /* Given two basic sets i and j,
1575 * check if relaxing all the cut constraints of i by one turns
1576 * them into valid constraint for j and check if we can wrap in
1577 * the bits that are sticking out.
1578 * If so, replace the pair by their union.
1580 * We first check if all relaxed cut inequalities of i are valid for j
1581 * and then try to wrap in the intersections of the relaxed cut inequalities
1584 * During this wrapping, we consider the points of j that lie at a distance
1585 * of exactly 1 from i. In particular, we ignore the points that lie in
1586 * between this lower-dimensional space and the basic map i.
1587 * We can therefore only apply this to integer maps.
1613 * Wrapping can fail if the result of wrapping one of the facets
1614 * around its edges does not produce any new facet constraint.
1615 * In particular, this happens when we try to wrap in unbounded sets.
1617 * _______________________________________________________________________
1621 * |_| |_________________________________________________________________
1624 * The following is not an acceptable result of coalescing the above two
1625 * sets as it includes extra integer points.
1626 * _______________________________________________________________________
1631 * \______________________________________________________________________
1633 static enum isl_change
can_wrap_in_set(int i
, int j
,
1634 struct isl_coalesce_info
*info
)
1640 if (ISL_F_ISSET(info
[i
].bmap
, ISL_BASIC_MAP_RATIONAL
) ||
1641 ISL_F_ISSET(info
[j
].bmap
, ISL_BASIC_MAP_RATIONAL
))
1642 return isl_change_none
;
1644 n
= count(info
[i
].eq
, 2 * info
[i
].bmap
->n_eq
, STATUS_CUT
);
1645 n
+= count(info
[i
].ineq
, info
[i
].bmap
->n_ineq
, STATUS_CUT
);
1647 return isl_change_none
;
1649 total
= isl_basic_map_total_dim(info
[i
].bmap
);
1650 for (k
= 0; k
< info
[i
].bmap
->n_eq
; ++k
) {
1651 for (l
= 0; l
< 2; ++l
) {
1652 enum isl_ineq_type type
;
1654 if (info
[i
].eq
[2 * k
+ l
] != STATUS_CUT
)
1658 isl_seq_neg(info
[i
].bmap
->eq
[k
],
1659 info
[i
].bmap
->eq
[k
], 1 + total
);
1660 type
= type_of_relaxed(info
[j
].tab
,
1661 info
[i
].bmap
->eq
[k
]);
1663 isl_seq_neg(info
[i
].bmap
->eq
[k
],
1664 info
[i
].bmap
->eq
[k
], 1 + total
);
1665 if (type
== isl_ineq_error
)
1666 return isl_change_error
;
1667 if (type
!= isl_ineq_redundant
)
1668 return isl_change_none
;
1672 for (k
= 0; k
< info
[i
].bmap
->n_ineq
; ++k
) {
1673 enum isl_ineq_type type
;
1675 if (info
[i
].ineq
[k
] != STATUS_CUT
)
1678 type
= type_of_relaxed(info
[j
].tab
, info
[i
].bmap
->ineq
[k
]);
1679 if (type
== isl_ineq_error
)
1680 return isl_change_error
;
1681 if (type
!= isl_ineq_redundant
)
1682 return isl_change_none
;
1685 return wrap_in_facets(i
, j
, n
, info
);
1688 /* Check if either i or j has only cut constraints that can
1689 * be used to wrap in (a facet of) the other basic set.
1690 * if so, replace the pair by their union.
1692 static enum isl_change
check_wrap(int i
, int j
, struct isl_coalesce_info
*info
)
1694 enum isl_change change
= isl_change_none
;
1696 change
= can_wrap_in_set(i
, j
, info
);
1697 if (change
!= isl_change_none
)
1700 change
= can_wrap_in_set(j
, i
, info
);
1704 /* At least one of the basic maps has an equality that is adjacent
1705 * to inequality. Make sure that only one of the basic maps has
1706 * such an equality and that the other basic map has exactly one
1707 * inequality adjacent to an equality.
1708 * If the other basic map does not have such an inequality, then
1709 * check if all its constraints are either valid or cut constraints
1710 * and, if so, try wrapping in the first map into the second.
1712 * We call the basic map that has the inequality "i" and the basic
1713 * map that has the equality "j".
1714 * If "i" has any "cut" (in)equality, then relaxing the inequality
1715 * by one would not result in a basic map that contains the other
1716 * basic map. However, it may still be possible to wrap in the other
1719 static enum isl_change
check_adj_eq(int i
, int j
,
1720 struct isl_coalesce_info
*info
)
1722 enum isl_change change
= isl_change_none
;
1726 if (any(info
[i
].eq
, 2 * info
[i
].bmap
->n_eq
, STATUS_ADJ_INEQ
) &&
1727 any(info
[j
].eq
, 2 * info
[j
].bmap
->n_eq
, STATUS_ADJ_INEQ
))
1728 /* ADJ EQ TOO MANY */
1729 return isl_change_none
;
1731 if (any(info
[i
].eq
, 2 * info
[i
].bmap
->n_eq
, STATUS_ADJ_INEQ
))
1732 return check_adj_eq(j
, i
, info
);
1734 /* j has an equality adjacent to an inequality in i */
1736 if (count(info
[i
].ineq
, info
[i
].bmap
->n_ineq
, STATUS_ADJ_EQ
) != 1) {
1737 if (all_valid_or_cut(&info
[i
]))
1738 return can_wrap_in_set(i
, j
, info
);
1739 return isl_change_none
;
1741 if (any(info
[i
].eq
, 2 * info
[i
].bmap
->n_eq
, STATUS_CUT
))
1742 return isl_change_none
;
1743 any_cut
= any(info
[i
].ineq
, info
[i
].bmap
->n_ineq
, STATUS_CUT
);
1744 if (any(info
[j
].ineq
, info
[j
].bmap
->n_ineq
, STATUS_ADJ_EQ
) ||
1745 any(info
[i
].ineq
, info
[i
].bmap
->n_ineq
, STATUS_ADJ_INEQ
) ||
1746 any(info
[j
].ineq
, info
[j
].bmap
->n_ineq
, STATUS_ADJ_INEQ
))
1747 /* ADJ EQ TOO MANY */
1748 return isl_change_none
;
1750 k
= find(info
[i
].ineq
, info
[i
].bmap
->n_ineq
, STATUS_ADJ_EQ
);
1753 change
= is_adj_eq_extension(i
, j
, k
, info
);
1754 if (change
!= isl_change_none
)
1758 change
= can_wrap_in_facet(i
, j
, k
, info
, any_cut
);
1763 /* The two basic maps lie on adjacent hyperplanes. In particular,
1764 * basic map "i" has an equality that lies parallel to basic map "j".
1765 * Check if we can wrap the facets around the parallel hyperplanes
1766 * to include the other set.
1768 * We perform basically the same operations as can_wrap_in_facet,
1769 * except that we don't need to select a facet of one of the sets.
1775 * If there is more than one equality of "i" adjacent to an equality of "j",
1776 * then the result will satisfy one or more equalities that are a linear
1777 * combination of these equalities. These will be encoded as pairs
1778 * of inequalities in the wrapping constraints and need to be made
1781 static enum isl_change
check_eq_adj_eq(int i
, int j
,
1782 struct isl_coalesce_info
*info
)
1785 enum isl_change change
= isl_change_none
;
1786 int detect_equalities
= 0;
1787 struct isl_wraps wraps
;
1790 struct isl_set
*set_i
= NULL
;
1791 struct isl_set
*set_j
= NULL
;
1792 struct isl_vec
*bound
= NULL
;
1793 unsigned total
= isl_basic_map_total_dim(info
[i
].bmap
);
1795 if (count(info
[i
].eq
, 2 * info
[i
].bmap
->n_eq
, STATUS_ADJ_EQ
) != 1)
1796 detect_equalities
= 1;
1798 k
= find(info
[i
].eq
, 2 * info
[i
].bmap
->n_eq
, STATUS_ADJ_EQ
);
1800 set_i
= set_from_updated_bmap(info
[i
].bmap
, info
[i
].tab
);
1801 set_j
= set_from_updated_bmap(info
[j
].bmap
, info
[j
].tab
);
1802 ctx
= isl_basic_map_get_ctx(info
[i
].bmap
);
1803 mat
= isl_mat_alloc(ctx
, 2 * (info
[i
].bmap
->n_eq
+ info
[j
].bmap
->n_eq
) +
1804 info
[i
].bmap
->n_ineq
+ info
[j
].bmap
->n_ineq
,
1806 wraps_init(&wraps
, mat
, info
, i
, j
);
1807 bound
= isl_vec_alloc(ctx
, 1 + total
);
1808 if (!set_i
|| !set_j
|| !wraps
.mat
|| !bound
)
1812 isl_seq_neg(bound
->el
, info
[i
].bmap
->eq
[k
/ 2], 1 + total
);
1814 isl_seq_cpy(bound
->el
, info
[i
].bmap
->eq
[k
/ 2], 1 + total
);
1815 isl_int_add_ui(bound
->el
[0], bound
->el
[0], 1);
1817 isl_seq_cpy(wraps
.mat
->row
[0], bound
->el
, 1 + total
);
1818 wraps
.mat
->n_row
= 1;
1820 if (add_wraps(&wraps
, &info
[j
], bound
->el
, set_i
) < 0)
1822 if (!wraps
.mat
->n_row
)
1825 isl_int_sub_ui(bound
->el
[0], bound
->el
[0], 1);
1826 isl_seq_neg(bound
->el
, bound
->el
, 1 + total
);
1828 isl_seq_cpy(wraps
.mat
->row
[wraps
.mat
->n_row
], bound
->el
, 1 + total
);
1831 if (add_wraps(&wraps
, &info
[i
], bound
->el
, set_j
) < 0)
1833 if (!wraps
.mat
->n_row
)
1836 change
= fuse(i
, j
, info
, wraps
.mat
, detect_equalities
, 0);
1839 error
: change
= isl_change_error
;
1844 isl_set_free(set_i
);
1845 isl_set_free(set_j
);
1846 isl_vec_free(bound
);
1851 /* Initialize the "eq" and "ineq" fields of "info".
1853 static void init_status(struct isl_coalesce_info
*info
)
1855 info
->eq
= info
->ineq
= NULL
;
1858 /* Set info->eq to the positions of the equalities of info->bmap
1859 * with respect to the basic map represented by "tab".
1860 * If info->eq has already been computed, then do not compute it again.
1862 static void set_eq_status_in(struct isl_coalesce_info
*info
,
1863 struct isl_tab
*tab
)
1867 info
->eq
= eq_status_in(info
->bmap
, tab
);
1870 /* Set info->ineq to the positions of the inequalities of info->bmap
1871 * with respect to the basic map represented by "tab".
1872 * If info->ineq has already been computed, then do not compute it again.
1874 static void set_ineq_status_in(struct isl_coalesce_info
*info
,
1875 struct isl_tab
*tab
)
1879 info
->ineq
= ineq_status_in(info
->bmap
, info
->tab
, tab
);
1882 /* Free the memory allocated by the "eq" and "ineq" fields of "info".
1883 * This function assumes that init_status has been called on "info" first,
1884 * after which the "eq" and "ineq" fields may or may not have been
1885 * assigned a newly allocated array.
1887 static void clear_status(struct isl_coalesce_info
*info
)
1893 /* Check if the union of the given pair of basic maps
1894 * can be represented by a single basic map.
1895 * If so, replace the pair by the single basic map and return
1896 * isl_change_drop_first, isl_change_drop_second or isl_change_fuse.
1897 * Otherwise, return isl_change_none.
1898 * The two basic maps are assumed to live in the same local space.
1899 * The "eq" and "ineq" fields of info[i] and info[j] are assumed
1900 * to have been initialized by the caller, either to NULL or
1901 * to valid information.
1903 * We first check the effect of each constraint of one basic map
1904 * on the other basic map.
1905 * The constraint may be
1906 * redundant the constraint is redundant in its own
1907 * basic map and should be ignore and removed
1909 * valid all (integer) points of the other basic map
1910 * satisfy the constraint
1911 * separate no (integer) point of the other basic map
1912 * satisfies the constraint
1913 * cut some but not all points of the other basic map
1914 * satisfy the constraint
1915 * adj_eq the given constraint is adjacent (on the outside)
1916 * to an equality of the other basic map
1917 * adj_ineq the given constraint is adjacent (on the outside)
1918 * to an inequality of the other basic map
1920 * We consider seven cases in which we can replace the pair by a single
1921 * basic map. We ignore all "redundant" constraints.
1923 * 1. all constraints of one basic map are valid
1924 * => the other basic map is a subset and can be removed
1926 * 2. all constraints of both basic maps are either "valid" or "cut"
1927 * and the facets corresponding to the "cut" constraints
1928 * of one of the basic maps lies entirely inside the other basic map
1929 * => the pair can be replaced by a basic map consisting
1930 * of the valid constraints in both basic maps
1932 * 3. there is a single pair of adjacent inequalities
1933 * (all other constraints are "valid")
1934 * => the pair can be replaced by a basic map consisting
1935 * of the valid constraints in both basic maps
1937 * 4. one basic map has a single adjacent inequality, while the other
1938 * constraints are "valid". The other basic map has some
1939 * "cut" constraints, but replacing the adjacent inequality by
1940 * its opposite and adding the valid constraints of the other
1941 * basic map results in a subset of the other basic map
1942 * => the pair can be replaced by a basic map consisting
1943 * of the valid constraints in both basic maps
1945 * 5. there is a single adjacent pair of an inequality and an equality,
1946 * the other constraints of the basic map containing the inequality are
1947 * "valid". Moreover, if the inequality the basic map is relaxed
1948 * and then turned into an equality, then resulting facet lies
1949 * entirely inside the other basic map
1950 * => the pair can be replaced by the basic map containing
1951 * the inequality, with the inequality relaxed.
1953 * 6. there is a single adjacent pair of an inequality and an equality,
1954 * the other constraints of the basic map containing the inequality are
1955 * "valid". Moreover, the facets corresponding to both
1956 * the inequality and the equality can be wrapped around their
1957 * ridges to include the other basic map
1958 * => the pair can be replaced by a basic map consisting
1959 * of the valid constraints in both basic maps together
1960 * with all wrapping constraints
1962 * 7. one of the basic maps extends beyond the other by at most one.
1963 * Moreover, the facets corresponding to the cut constraints and
1964 * the pieces of the other basic map at offset one from these cut
1965 * constraints can be wrapped around their ridges to include
1966 * the union of the two basic maps
1967 * => the pair can be replaced by a basic map consisting
1968 * of the valid constraints in both basic maps together
1969 * with all wrapping constraints
1971 * 8. the two basic maps live in adjacent hyperplanes. In principle
1972 * such sets can always be combined through wrapping, but we impose
1973 * that there is only one such pair, to avoid overeager coalescing.
1975 * Throughout the computation, we maintain a collection of tableaus
1976 * corresponding to the basic maps. When the basic maps are dropped
1977 * or combined, the tableaus are modified accordingly.
1979 static enum isl_change
coalesce_local_pair_reuse(int i
, int j
,
1980 struct isl_coalesce_info
*info
)
1982 enum isl_change change
= isl_change_none
;
1984 set_eq_status_in(&info
[i
], info
[j
].tab
);
1985 if (info
[i
].bmap
->n_eq
&& !info
[i
].eq
)
1987 if (any(info
[i
].eq
, 2 * info
[i
].bmap
->n_eq
, STATUS_ERROR
))
1989 if (any(info
[i
].eq
, 2 * info
[i
].bmap
->n_eq
, STATUS_SEPARATE
))
1992 set_eq_status_in(&info
[j
], info
[i
].tab
);
1993 if (info
[j
].bmap
->n_eq
&& !info
[j
].eq
)
1995 if (any(info
[j
].eq
, 2 * info
[j
].bmap
->n_eq
, STATUS_ERROR
))
1997 if (any(info
[j
].eq
, 2 * info
[j
].bmap
->n_eq
, STATUS_SEPARATE
))
2000 set_ineq_status_in(&info
[i
], info
[j
].tab
);
2001 if (info
[i
].bmap
->n_ineq
&& !info
[i
].ineq
)
2003 if (any(info
[i
].ineq
, info
[i
].bmap
->n_ineq
, STATUS_ERROR
))
2005 if (any(info
[i
].ineq
, info
[i
].bmap
->n_ineq
, STATUS_SEPARATE
))
2008 set_ineq_status_in(&info
[j
], info
[i
].tab
);
2009 if (info
[j
].bmap
->n_ineq
&& !info
[j
].ineq
)
2011 if (any(info
[j
].ineq
, info
[j
].bmap
->n_ineq
, STATUS_ERROR
))
2013 if (any(info
[j
].ineq
, info
[j
].bmap
->n_ineq
, STATUS_SEPARATE
))
2016 if (all(info
[i
].eq
, 2 * info
[i
].bmap
->n_eq
, STATUS_VALID
) &&
2017 all(info
[i
].ineq
, info
[i
].bmap
->n_ineq
, STATUS_VALID
)) {
2019 change
= isl_change_drop_second
;
2020 } else if (all(info
[j
].eq
, 2 * info
[j
].bmap
->n_eq
, STATUS_VALID
) &&
2021 all(info
[j
].ineq
, info
[j
].bmap
->n_ineq
, STATUS_VALID
)) {
2023 change
= isl_change_drop_first
;
2024 } else if (any(info
[i
].eq
, 2 * info
[i
].bmap
->n_eq
, STATUS_ADJ_EQ
)) {
2025 change
= check_eq_adj_eq(i
, j
, info
);
2026 } else if (any(info
[j
].eq
, 2 * info
[j
].bmap
->n_eq
, STATUS_ADJ_EQ
)) {
2027 change
= check_eq_adj_eq(j
, i
, info
);
2028 } else if (any(info
[i
].eq
, 2 * info
[i
].bmap
->n_eq
, STATUS_ADJ_INEQ
) ||
2029 any(info
[j
].eq
, 2 * info
[j
].bmap
->n_eq
, STATUS_ADJ_INEQ
)) {
2030 change
= check_adj_eq(i
, j
, info
);
2031 } else if (any(info
[i
].ineq
, info
[i
].bmap
->n_ineq
, STATUS_ADJ_EQ
) ||
2032 any(info
[j
].ineq
, info
[j
].bmap
->n_ineq
, STATUS_ADJ_EQ
)) {
2035 } else if (any(info
[i
].ineq
, info
[i
].bmap
->n_ineq
, STATUS_ADJ_INEQ
) ||
2036 any(info
[j
].ineq
, info
[j
].bmap
->n_ineq
, STATUS_ADJ_INEQ
)) {
2037 change
= check_adj_ineq(i
, j
, info
);
2039 if (!any(info
[i
].eq
, 2 * info
[i
].bmap
->n_eq
, STATUS_CUT
) &&
2040 !any(info
[j
].eq
, 2 * info
[j
].bmap
->n_eq
, STATUS_CUT
))
2041 change
= check_facets(i
, j
, info
);
2042 if (change
== isl_change_none
)
2043 change
= check_wrap(i
, j
, info
);
2047 clear_status(&info
[i
]);
2048 clear_status(&info
[j
]);
2051 clear_status(&info
[i
]);
2052 clear_status(&info
[j
]);
2053 return isl_change_error
;
2056 /* Check if the union of the given pair of basic maps
2057 * can be represented by a single basic map.
2058 * If so, replace the pair by the single basic map and return
2059 * isl_change_drop_first, isl_change_drop_second or isl_change_fuse.
2060 * Otherwise, return isl_change_none.
2061 * The two basic maps are assumed to live in the same local space.
2063 static enum isl_change
coalesce_local_pair(int i
, int j
,
2064 struct isl_coalesce_info
*info
)
2066 init_status(&info
[i
]);
2067 init_status(&info
[j
]);
2068 return coalesce_local_pair_reuse(i
, j
, info
);
2071 /* Shift the integer division at position "div" of the basic map
2072 * represented by "info" by "shift".
2074 * That is, if the integer division has the form
2078 * then replace it by
2080 * floor((f(x) + shift * d)/d) - shift
2082 static int shift_div(struct isl_coalesce_info
*info
, int div
, isl_int shift
)
2086 info
->bmap
= isl_basic_map_shift_div(info
->bmap
, div
, 0, shift
);
2090 total
= isl_basic_map_dim(info
->bmap
, isl_dim_all
);
2091 total
-= isl_basic_map_dim(info
->bmap
, isl_dim_div
);
2092 if (isl_tab_shift_var(info
->tab
, total
+ div
, shift
) < 0)
2098 /* Check if some of the divs in the basic map represented by "info1"
2099 * are shifts of the corresponding divs in the basic map represented
2100 * by "info2". If so, align them with those of "info2".
2101 * Only do this if "info1" and "info2" have the same number
2102 * of integer divisions.
2104 * An integer division is considered to be a shift of another integer
2105 * division if one is equal to the other plus a constant.
2107 * In particular, for each pair of integer divisions, if both are known,
2108 * have identical coefficients (apart from the constant term) and
2109 * if the difference between the constant terms (taking into account
2110 * the denominator) is an integer, then move the difference outside.
2111 * That is, if one integer division is of the form
2113 * floor((f(x) + c_1)/d)
2115 * while the other is of the form
2117 * floor((f(x) + c_2)/d)
2119 * and n = (c_2 - c_1)/d is an integer, then replace the first
2120 * integer division by
2122 * floor((f(x) + c_1 + n * d)/d) - n = floor((f(x) + c_2)/d) - n
2124 static int harmonize_divs(struct isl_coalesce_info
*info1
,
2125 struct isl_coalesce_info
*info2
)
2130 if (!info1
->bmap
|| !info2
->bmap
)
2133 if (info1
->bmap
->n_div
!= info2
->bmap
->n_div
)
2135 if (info1
->bmap
->n_div
== 0)
2138 total
= isl_basic_map_total_dim(info1
->bmap
);
2139 for (i
= 0; i
< info1
->bmap
->n_div
; ++i
) {
2143 if (isl_int_is_zero(info1
->bmap
->div
[i
][0]) ||
2144 isl_int_is_zero(info2
->bmap
->div
[i
][0]))
2146 if (isl_int_ne(info1
->bmap
->div
[i
][0], info2
->bmap
->div
[i
][0]))
2148 if (isl_int_eq(info1
->bmap
->div
[i
][1], info2
->bmap
->div
[i
][1]))
2150 if (!isl_seq_eq(info1
->bmap
->div
[i
] + 2,
2151 info2
->bmap
->div
[i
] + 2, total
))
2154 isl_int_sub(d
, info2
->bmap
->div
[i
][1], info1
->bmap
->div
[i
][1]);
2155 if (isl_int_is_divisible_by(d
, info1
->bmap
->div
[i
][0])) {
2156 isl_int_divexact(d
, d
, info1
->bmap
->div
[i
][0]);
2157 r
= shift_div(info1
, i
, d
);
2167 /* Do the two basic maps live in the same local space, i.e.,
2168 * do they have the same (known) divs?
2169 * If either basic map has any unknown divs, then we can only assume
2170 * that they do not live in the same local space.
2172 static int same_divs(__isl_keep isl_basic_map
*bmap1
,
2173 __isl_keep isl_basic_map
*bmap2
)
2179 if (!bmap1
|| !bmap2
)
2181 if (bmap1
->n_div
!= bmap2
->n_div
)
2184 if (bmap1
->n_div
== 0)
2187 known
= isl_basic_map_divs_known(bmap1
);
2188 if (known
< 0 || !known
)
2190 known
= isl_basic_map_divs_known(bmap2
);
2191 if (known
< 0 || !known
)
2194 total
= isl_basic_map_total_dim(bmap1
);
2195 for (i
= 0; i
< bmap1
->n_div
; ++i
)
2196 if (!isl_seq_eq(bmap1
->div
[i
], bmap2
->div
[i
], 2 + total
))
2202 /* Expand info->tab in the same way info->bmap was expanded in
2203 * isl_basic_map_expand_divs using the expansion "exp" and
2204 * update info->ineq with respect to the redundant constraints
2205 * in the resulting tableau. "bmap" is the original version
2206 * of info->bmap, i.e., the one that corresponds to the current
2207 * state of info->tab. The number of constraints in "bmap"
2208 * is assumed to be the same as the number of constraints
2209 * in info->tab. This is required to be able to detect
2210 * the extra constraints in info->bmap.
2212 * In particular, introduce extra variables corresponding
2213 * to the extra integer divisions and add the div constraints
2214 * that were added to info->bmap after info->tab was created
2215 * from the original info->bmap.
2216 * info->ineq was computed without a tableau and therefore
2217 * does not take into account the redundant constraints
2218 * in the tableau. Mark them here.
2220 static isl_stat
expand_tab(struct isl_coalesce_info
*info
, int *exp
,
2221 __isl_keep isl_basic_map
*bmap
)
2223 unsigned total
, pos
, n_div
;
2225 int i
, n
, j
, n_ineq
;
2229 return isl_stat_error
;
2230 if (bmap
->n_eq
+ bmap
->n_ineq
!= info
->tab
->n_con
)
2231 isl_die(isl_basic_map_get_ctx(bmap
), isl_error_internal
,
2232 "original tableau does not correspond "
2233 "to original basic map", return isl_stat_error
);
2235 total
= isl_basic_map_dim(info
->bmap
, isl_dim_all
);
2236 n_div
= isl_basic_map_dim(info
->bmap
, isl_dim_div
);
2237 pos
= total
- n_div
;
2238 extra_var
= total
- info
->tab
->n_var
;
2239 n
= n_div
- extra_var
;
2241 if (isl_tab_extend_vars(info
->tab
, extra_var
) < 0)
2242 return isl_stat_error
;
2243 if (isl_tab_extend_cons(info
->tab
, 2 * extra_var
) < 0)
2244 return isl_stat_error
;
2247 for (j
= 0; j
< n_div
; ++j
) {
2248 if (i
< n
&& exp
[i
] == j
) {
2252 if (isl_tab_insert_var(info
->tab
, pos
+ j
) < 0)
2253 return isl_stat_error
;
2256 n_ineq
= info
->tab
->n_con
- info
->tab
->n_eq
;
2257 for (i
= n_ineq
; i
< info
->bmap
->n_ineq
; ++i
)
2258 if (isl_tab_add_ineq(info
->tab
, info
->bmap
->ineq
[i
]) < 0)
2259 return isl_stat_error
;
2261 n_eq
= info
->bmap
->n_eq
;
2262 for (i
= 0; i
< info
->bmap
->n_ineq
; ++i
) {
2263 if (isl_tab_is_redundant(info
->tab
, n_eq
+ i
))
2264 info
->ineq
[i
] = STATUS_REDUNDANT
;
2270 /* Check if the union of the basic maps represented by info[i] and info[j]
2271 * can be represented by a single basic map,
2272 * after expanding the divs of info[i] to match those of info[j].
2273 * If so, replace the pair by the single basic map and return
2274 * isl_change_drop_first, isl_change_drop_second or isl_change_fuse.
2275 * Otherwise, return isl_change_none.
2277 * The caller has already checked for info[j] being a subset of info[i].
2278 * If some of the divs of info[j] are unknown, then the expanded info[i]
2279 * will not have the corresponding div constraints. The other patterns
2280 * therefore cannot apply. Skip the computation in this case.
2282 * The expansion is performed using the divs "div" and expansion "exp"
2283 * computed by the caller.
2284 * info[i].bmap has already been expanded and the result is passed in
2286 * The "eq" and "ineq" fields of info[i] reflect the status of
2287 * the constraints of the expanded "bmap" with respect to info[j].tab.
2288 * However, inequality constraints that are redundant in info[i].tab
2289 * have not yet been marked as such because no tableau was available.
2291 * Replace info[i].bmap by "bmap" and expand info[i].tab as well,
2292 * updating info[i].ineq with respect to the redundant constraints.
2293 * Then try and coalesce the expanded info[i] with info[j],
2294 * reusing the information in info[i].eq and info[i].ineq.
2295 * If this does not result in any coalescing or if it results in info[j]
2296 * getting dropped (which should not happen in practice, since the case
2297 * of info[j] being a subset of info[i] has already been checked by
2298 * the caller), then revert info[i] to its original state.
2300 static enum isl_change
coalesce_expand_tab_divs(__isl_take isl_basic_map
*bmap
,
2301 int i
, int j
, struct isl_coalesce_info
*info
, __isl_keep isl_mat
*div
,
2305 isl_basic_map
*bmap_i
;
2306 struct isl_tab_undo
*snap
;
2307 enum isl_change change
= isl_change_none
;
2309 known
= isl_basic_map_divs_known(info
[j
].bmap
);
2310 if (known
< 0 || !known
) {
2311 clear_status(&info
[i
]);
2312 isl_basic_map_free(bmap
);
2313 return known
< 0 ? isl_change_error
: isl_change_none
;
2316 bmap_i
= info
[i
].bmap
;
2317 info
[i
].bmap
= isl_basic_map_copy(bmap
);
2318 snap
= isl_tab_snap(info
[i
].tab
);
2319 if (!info
[i
].bmap
|| expand_tab(&info
[i
], exp
, bmap_i
) < 0)
2320 change
= isl_change_error
;
2322 init_status(&info
[j
]);
2323 if (change
== isl_change_none
)
2324 change
= coalesce_local_pair_reuse(i
, j
, info
);
2326 clear_status(&info
[i
]);
2327 if (change
!= isl_change_none
&& change
!= isl_change_drop_second
) {
2328 isl_basic_map_free(bmap_i
);
2330 isl_basic_map_free(info
[i
].bmap
);
2331 info
[i
].bmap
= bmap_i
;
2333 if (isl_tab_rollback(info
[i
].tab
, snap
) < 0)
2334 change
= isl_change_error
;
2337 isl_basic_map_free(bmap
);
2341 /* Check if the union of "bmap" and the basic map represented by info[j]
2342 * can be represented by a single basic map,
2343 * after expanding the divs of "bmap" to match those of info[j].
2344 * If so, replace the pair by the single basic map and return
2345 * isl_change_drop_first, isl_change_drop_second or isl_change_fuse.
2346 * Otherwise, return isl_change_none.
2348 * In particular, check if the expanded "bmap" contains the basic map
2349 * represented by the tableau info[j].tab.
2350 * The expansion is performed using the divs "div" and expansion "exp"
2351 * computed by the caller.
2352 * Then we check if all constraints of the expanded "bmap" are valid for
2355 * If "i" is not equal to -1, then "bmap" is equal to info[i].bmap.
2356 * In this case, the positions of the constraints of info[i].bmap
2357 * with respect to the basic map represented by info[j] are stored
2360 * If the expanded "bmap" does not contain the basic map
2361 * represented by the tableau info[j].tab and if "i" is not -1,
2362 * i.e., if the original "bmap" is info[i].bmap, then expand info[i].tab
2363 * as well and check if that results in coalescing.
2365 static enum isl_change
coalesce_with_expanded_divs(
2366 __isl_keep isl_basic_map
*bmap
, int i
, int j
,
2367 struct isl_coalesce_info
*info
, __isl_keep isl_mat
*div
, int *exp
)
2369 enum isl_change change
= isl_change_none
;
2370 struct isl_coalesce_info info_local
, *info_i
;
2372 info_i
= i
>= 0 ? &info
[i
] : &info_local
;
2373 init_status(info_i
);
2374 bmap
= isl_basic_map_copy(bmap
);
2375 bmap
= isl_basic_map_expand_divs(bmap
, isl_mat_copy(div
), exp
);
2376 bmap
= isl_basic_map_mark_final(bmap
);
2381 info_i
->eq
= eq_status_in(bmap
, info
[j
].tab
);
2382 if (bmap
->n_eq
&& !info_i
->eq
)
2384 if (any(info_i
->eq
, 2 * bmap
->n_eq
, STATUS_ERROR
))
2386 if (any(info_i
->eq
, 2 * bmap
->n_eq
, STATUS_SEPARATE
))
2389 info_i
->ineq
= ineq_status_in(bmap
, NULL
, info
[j
].tab
);
2390 if (bmap
->n_ineq
&& !info_i
->ineq
)
2392 if (any(info_i
->ineq
, bmap
->n_ineq
, STATUS_ERROR
))
2394 if (any(info_i
->ineq
, bmap
->n_ineq
, STATUS_SEPARATE
))
2397 if (all(info_i
->eq
, 2 * bmap
->n_eq
, STATUS_VALID
) &&
2398 all(info_i
->ineq
, bmap
->n_ineq
, STATUS_VALID
)) {
2400 change
= isl_change_drop_second
;
2403 if (change
== isl_change_none
&& i
!= -1)
2404 return coalesce_expand_tab_divs(bmap
, i
, j
, info
, div
, exp
);
2407 isl_basic_map_free(bmap
);
2408 clear_status(info_i
);
2411 isl_basic_map_free(bmap
);
2412 clear_status(info_i
);
2413 return isl_change_error
;
2416 /* Check if the union of "bmap_i" and the basic map represented by info[j]
2417 * can be represented by a single basic map,
2418 * after aligning the divs of "bmap_i" to match those of info[j].
2419 * If so, replace the pair by the single basic map and return
2420 * isl_change_drop_first, isl_change_drop_second or isl_change_fuse.
2421 * Otherwise, return isl_change_none.
2423 * In particular, check if "bmap_i" contains the basic map represented by
2424 * info[j] after aligning the divs of "bmap_i" to those of info[j].
2425 * Note that this can only succeed if the number of divs of "bmap_i"
2426 * is smaller than (or equal to) the number of divs of info[j].
2428 * We first check if the divs of "bmap_i" are all known and form a subset
2429 * of those of info[j].bmap. If so, we pass control over to
2430 * coalesce_with_expanded_divs.
2432 * If "i" is not equal to -1, then "bmap" is equal to info[i].bmap.
2434 static enum isl_change
coalesce_after_aligning_divs(
2435 __isl_keep isl_basic_map
*bmap_i
, int i
, int j
,
2436 struct isl_coalesce_info
*info
)
2439 isl_mat
*div_i
, *div_j
, *div
;
2443 enum isl_change change
;
2445 known
= isl_basic_map_divs_known(bmap_i
);
2446 if (known
< 0 || !known
)
2449 ctx
= isl_basic_map_get_ctx(bmap_i
);
2451 div_i
= isl_basic_map_get_divs(bmap_i
);
2452 div_j
= isl_basic_map_get_divs(info
[j
].bmap
);
2454 if (!div_i
|| !div_j
)
2457 exp1
= isl_alloc_array(ctx
, int, div_i
->n_row
);
2458 exp2
= isl_alloc_array(ctx
, int, div_j
->n_row
);
2459 if ((div_i
->n_row
&& !exp1
) || (div_j
->n_row
&& !exp2
))
2462 div
= isl_merge_divs(div_i
, div_j
, exp1
, exp2
);
2466 if (div
->n_row
== div_j
->n_row
)
2467 change
= coalesce_with_expanded_divs(bmap_i
,
2468 i
, j
, info
, div
, exp1
);
2470 change
= isl_change_none
;
2474 isl_mat_free(div_i
);
2475 isl_mat_free(div_j
);
2482 isl_mat_free(div_i
);
2483 isl_mat_free(div_j
);
2486 return isl_change_error
;
2489 /* Check if basic map "j" is a subset of basic map "i" after
2490 * exploiting the extra equalities of "j" to simplify the divs of "i".
2491 * If so, remove basic map "j" and return isl_change_drop_second.
2493 * If "j" does not have any equalities or if they are the same
2494 * as those of "i", then we cannot exploit them to simplify the divs.
2495 * Similarly, if there are no divs in "i", then they cannot be simplified.
2496 * If, on the other hand, the affine hulls of "i" and "j" do not intersect,
2497 * then "j" cannot be a subset of "i".
2499 * Otherwise, we intersect "i" with the affine hull of "j" and then
2500 * check if "j" is a subset of the result after aligning the divs.
2501 * If so, then "j" is definitely a subset of "i" and can be removed.
2502 * Note that if after intersection with the affine hull of "j".
2503 * "i" still has more divs than "j", then there is no way we can
2504 * align the divs of "i" to those of "j".
2506 static enum isl_change
coalesce_subset_with_equalities(int i
, int j
,
2507 struct isl_coalesce_info
*info
)
2509 isl_basic_map
*hull_i
, *hull_j
, *bmap_i
;
2511 enum isl_change change
;
2513 if (info
[j
].bmap
->n_eq
== 0)
2514 return isl_change_none
;
2515 if (info
[i
].bmap
->n_div
== 0)
2516 return isl_change_none
;
2518 hull_i
= isl_basic_map_copy(info
[i
].bmap
);
2519 hull_i
= isl_basic_map_plain_affine_hull(hull_i
);
2520 hull_j
= isl_basic_map_copy(info
[j
].bmap
);
2521 hull_j
= isl_basic_map_plain_affine_hull(hull_j
);
2523 hull_j
= isl_basic_map_intersect(hull_j
, isl_basic_map_copy(hull_i
));
2524 equal
= isl_basic_map_plain_is_equal(hull_i
, hull_j
);
2525 empty
= isl_basic_map_plain_is_empty(hull_j
);
2526 isl_basic_map_free(hull_i
);
2528 if (equal
< 0 || equal
|| empty
< 0 || empty
) {
2529 isl_basic_map_free(hull_j
);
2530 if (equal
< 0 || empty
< 0)
2531 return isl_change_error
;
2532 return isl_change_none
;
2535 bmap_i
= isl_basic_map_copy(info
[i
].bmap
);
2536 bmap_i
= isl_basic_map_intersect(bmap_i
, hull_j
);
2538 return isl_change_error
;
2540 if (bmap_i
->n_div
> info
[j
].bmap
->n_div
) {
2541 isl_basic_map_free(bmap_i
);
2542 return isl_change_none
;
2545 change
= coalesce_after_aligning_divs(bmap_i
, -1, j
, info
);
2547 isl_basic_map_free(bmap_i
);
2552 /* Check if the union of and the basic maps represented by info[i] and info[j]
2553 * can be represented by a single basic map, by aligning or equating
2554 * their integer divisions.
2555 * If so, replace the pair by the single basic map and return
2556 * isl_change_drop_first, isl_change_drop_second or isl_change_fuse.
2557 * Otherwise, return isl_change_none.
2559 * Note that we only perform any test if the number of divs is different
2560 * in the two basic maps. In case the number of divs is the same,
2561 * we have already established that the divs are different
2562 * in the two basic maps.
2563 * In particular, if the number of divs of basic map i is smaller than
2564 * the number of divs of basic map j, then we check if j is a subset of i
2567 static enum isl_change
coalesce_divs(int i
, int j
,
2568 struct isl_coalesce_info
*info
)
2570 enum isl_change change
= isl_change_none
;
2572 if (info
[i
].bmap
->n_div
< info
[j
].bmap
->n_div
)
2573 change
= coalesce_after_aligning_divs(info
[i
].bmap
, i
, j
, info
);
2574 if (change
!= isl_change_none
)
2577 if (info
[j
].bmap
->n_div
< info
[i
].bmap
->n_div
)
2578 change
= coalesce_after_aligning_divs(info
[j
].bmap
, j
, i
, info
);
2579 if (change
!= isl_change_none
)
2580 return invert_change(change
);
2582 change
= coalesce_subset_with_equalities(i
, j
, info
);
2583 if (change
!= isl_change_none
)
2586 change
= coalesce_subset_with_equalities(j
, i
, info
);
2587 if (change
!= isl_change_none
)
2588 return invert_change(change
);
2590 return isl_change_none
;
2593 /* Does "bmap" involve any divs that themselves refer to divs?
2595 static int has_nested_div(__isl_keep isl_basic_map
*bmap
)
2601 total
= isl_basic_map_dim(bmap
, isl_dim_all
);
2602 n_div
= isl_basic_map_dim(bmap
, isl_dim_div
);
2605 for (i
= 0; i
< n_div
; ++i
)
2606 if (isl_seq_first_non_zero(bmap
->div
[i
] + 2 + total
,
2613 /* Return a list of affine expressions, one for each integer division
2614 * in "bmap_i". For each integer division that also appears in "bmap_j",
2615 * the affine expression is set to NaN. The number of NaNs in the list
2616 * is equal to the number of integer divisions in "bmap_j".
2617 * For the other integer divisions of "bmap_i", the corresponding
2618 * element in the list is a purely affine expression equal to the integer
2619 * division in "hull".
2620 * If no such list can be constructed, then the number of elements
2621 * in the returned list is smaller than the number of integer divisions
2624 static __isl_give isl_aff_list
*set_up_substitutions(
2625 __isl_keep isl_basic_map
*bmap_i
, __isl_keep isl_basic_map
*bmap_j
,
2626 __isl_take isl_basic_map
*hull
)
2628 unsigned n_div_i
, n_div_j
, total
;
2630 isl_local_space
*ls
;
2631 isl_basic_set
*wrap_hull
;
2639 ctx
= isl_basic_map_get_ctx(hull
);
2641 n_div_i
= isl_basic_map_dim(bmap_i
, isl_dim_div
);
2642 n_div_j
= isl_basic_map_dim(bmap_j
, isl_dim_div
);
2643 total
= isl_basic_map_total_dim(bmap_i
) - n_div_i
;
2645 ls
= isl_basic_map_get_local_space(bmap_i
);
2646 ls
= isl_local_space_wrap(ls
);
2647 wrap_hull
= isl_basic_map_wrap(hull
);
2649 aff_nan
= isl_aff_nan_on_domain(isl_local_space_copy(ls
));
2650 list
= isl_aff_list_alloc(ctx
, n_div_i
);
2653 for (i
= 0; i
< n_div_i
; ++i
) {
2657 isl_seq_eq(bmap_i
->div
[i
], bmap_j
->div
[j
], 2 + total
)) {
2659 list
= isl_aff_list_add(list
, isl_aff_copy(aff_nan
));
2662 if (n_div_i
- i
<= n_div_j
- j
)
2665 aff
= isl_local_space_get_div(ls
, i
);
2666 aff
= isl_aff_substitute_equalities(aff
,
2667 isl_basic_set_copy(wrap_hull
));
2668 aff
= isl_aff_floor(aff
);
2671 if (isl_aff_dim(aff
, isl_dim_div
) != 0) {
2676 list
= isl_aff_list_add(list
, aff
);
2679 isl_aff_free(aff_nan
);
2680 isl_local_space_free(ls
);
2681 isl_basic_set_free(wrap_hull
);
2685 isl_aff_free(aff_nan
);
2686 isl_local_space_free(ls
);
2687 isl_basic_set_free(wrap_hull
);
2688 isl_aff_list_free(list
);
2692 /* Add variables to info->bmap and info->tab corresponding to the elements
2693 * in "list" that are not set to NaN.
2694 * "extra_var" is the number of these elements.
2695 * "dim" is the offset in the variables of "tab" where we should
2696 * start considering the elements in "list".
2697 * When this function returns, the total number of variables in "tab"
2698 * is equal to "dim" plus the number of elements in "list".
2700 * The newly added existentially quantified variables are not given
2701 * an explicit representation because the corresponding div constraints
2702 * do not appear in info->bmap. These constraints are not added
2703 * to info->bmap because for internal consistency, they would need to
2704 * be added to info->tab as well, where they could combine with the equality
2705 * that is added later to result in constraints that do not hold
2706 * in the original input.
2708 static int add_sub_vars(struct isl_coalesce_info
*info
,
2709 __isl_keep isl_aff_list
*list
, int dim
, int extra_var
)
2714 space
= isl_basic_map_get_space(info
->bmap
);
2715 info
->bmap
= isl_basic_map_cow(info
->bmap
);
2716 info
->bmap
= isl_basic_map_extend_space(info
->bmap
, space
,
2720 n
= isl_aff_list_n_aff(list
);
2721 for (i
= 0; i
< n
; ++i
) {
2725 aff
= isl_aff_list_get_aff(list
, i
);
2726 is_nan
= isl_aff_is_nan(aff
);
2733 if (isl_tab_insert_var(info
->tab
, dim
+ i
) < 0)
2735 d
= isl_basic_map_alloc_div(info
->bmap
);
2738 info
->bmap
= isl_basic_map_mark_div_unknown(info
->bmap
, d
);
2741 for (j
= d
; j
> i
; --j
)
2742 isl_basic_map_swap_div(info
->bmap
, j
- 1, j
);
2748 /* For each element in "list" that is not set to NaN, fix the corresponding
2749 * variable in "tab" to the purely affine expression defined by the element.
2750 * "dim" is the offset in the variables of "tab" where we should
2751 * start considering the elements in "list".
2753 * This function assumes that a sufficient number of rows and
2754 * elements in the constraint array are available in the tableau.
2756 static int add_sub_equalities(struct isl_tab
*tab
,
2757 __isl_keep isl_aff_list
*list
, int dim
)
2764 n
= isl_aff_list_n_aff(list
);
2766 ctx
= isl_tab_get_ctx(tab
);
2767 sub
= isl_vec_alloc(ctx
, 1 + dim
+ n
);
2770 isl_seq_clr(sub
->el
+ 1 + dim
, n
);
2772 for (i
= 0; i
< n
; ++i
) {
2773 aff
= isl_aff_list_get_aff(list
, i
);
2776 if (isl_aff_is_nan(aff
)) {
2780 isl_seq_cpy(sub
->el
, aff
->v
->el
+ 1, 1 + dim
);
2781 isl_int_neg(sub
->el
[1 + dim
+ i
], aff
->v
->el
[0]);
2782 if (isl_tab_add_eq(tab
, sub
->el
) < 0)
2784 isl_int_set_si(sub
->el
[1 + dim
+ i
], 0);
2796 /* Add variables to info->tab and info->bmap corresponding to the elements
2797 * in "list" that are not set to NaN. The value of the added variable
2798 * in info->tab is fixed to the purely affine expression defined by the element.
2799 * "dim" is the offset in the variables of info->tab where we should
2800 * start considering the elements in "list".
2801 * When this function returns, the total number of variables in info->tab
2802 * is equal to "dim" plus the number of elements in "list".
2804 static int add_subs(struct isl_coalesce_info
*info
,
2805 __isl_keep isl_aff_list
*list
, int dim
)
2813 n
= isl_aff_list_n_aff(list
);
2814 extra_var
= n
- (info
->tab
->n_var
- dim
);
2816 if (isl_tab_extend_vars(info
->tab
, extra_var
) < 0)
2818 if (isl_tab_extend_cons(info
->tab
, 2 * extra_var
) < 0)
2820 if (add_sub_vars(info
, list
, dim
, extra_var
) < 0)
2823 return add_sub_equalities(info
->tab
, list
, dim
);
2826 /* Coalesce basic map "j" into basic map "i" after adding the extra integer
2827 * divisions in "i" but not in "j" to basic map "j", with values
2828 * specified by "list". The total number of elements in "list"
2829 * is equal to the number of integer divisions in "i", while the number
2830 * of NaN elements in the list is equal to the number of integer divisions
2833 * If no coalescing can be performed, then we need to revert basic map "j"
2834 * to its original state. We do the same if basic map "i" gets dropped
2835 * during the coalescing, even though this should not happen in practice
2836 * since we have already checked for "j" being a subset of "i"
2837 * before we reach this stage.
2839 static enum isl_change
coalesce_with_subs(int i
, int j
,
2840 struct isl_coalesce_info
*info
, __isl_keep isl_aff_list
*list
)
2842 isl_basic_map
*bmap_j
;
2843 struct isl_tab_undo
*snap
;
2845 enum isl_change change
;
2847 bmap_j
= isl_basic_map_copy(info
[j
].bmap
);
2848 snap
= isl_tab_snap(info
[j
].tab
);
2850 dim
= isl_basic_map_dim(bmap_j
, isl_dim_all
);
2851 dim
-= isl_basic_map_dim(bmap_j
, isl_dim_div
);
2852 if (add_subs(&info
[j
], list
, dim
) < 0)
2855 change
= coalesce_local_pair(i
, j
, info
);
2856 if (change
!= isl_change_none
&& change
!= isl_change_drop_first
) {
2857 isl_basic_map_free(bmap_j
);
2859 isl_basic_map_free(info
[j
].bmap
);
2860 info
[j
].bmap
= bmap_j
;
2862 if (isl_tab_rollback(info
[j
].tab
, snap
) < 0)
2863 return isl_change_error
;
2868 isl_basic_map_free(bmap_j
);
2869 return isl_change_error
;
2872 /* Check if we can coalesce basic map "j" into basic map "i" after copying
2873 * those extra integer divisions in "i" that can be simplified away
2874 * using the extra equalities in "j".
2875 * All divs are assumed to be known and not contain any nested divs.
2877 * We first check if there are any extra equalities in "j" that we
2878 * can exploit. Then we check if every integer division in "i"
2879 * either already appears in "j" or can be simplified using the
2880 * extra equalities to a purely affine expression.
2881 * If these tests succeed, then we try to coalesce the two basic maps
2882 * by introducing extra dimensions in "j" corresponding to
2883 * the extra integer divsisions "i" fixed to the corresponding
2884 * purely affine expression.
2886 static enum isl_change
check_coalesce_into_eq(int i
, int j
,
2887 struct isl_coalesce_info
*info
)
2889 unsigned n_div_i
, n_div_j
;
2890 isl_basic_map
*hull_i
, *hull_j
;
2893 enum isl_change change
;
2895 n_div_i
= isl_basic_map_dim(info
[i
].bmap
, isl_dim_div
);
2896 n_div_j
= isl_basic_map_dim(info
[j
].bmap
, isl_dim_div
);
2897 if (n_div_i
<= n_div_j
)
2898 return isl_change_none
;
2899 if (info
[j
].bmap
->n_eq
== 0)
2900 return isl_change_none
;
2902 hull_i
= isl_basic_map_copy(info
[i
].bmap
);
2903 hull_i
= isl_basic_map_plain_affine_hull(hull_i
);
2904 hull_j
= isl_basic_map_copy(info
[j
].bmap
);
2905 hull_j
= isl_basic_map_plain_affine_hull(hull_j
);
2907 hull_j
= isl_basic_map_intersect(hull_j
, isl_basic_map_copy(hull_i
));
2908 equal
= isl_basic_map_plain_is_equal(hull_i
, hull_j
);
2909 empty
= isl_basic_map_plain_is_empty(hull_j
);
2910 isl_basic_map_free(hull_i
);
2912 if (equal
< 0 || empty
< 0)
2914 if (equal
|| empty
) {
2915 isl_basic_map_free(hull_j
);
2916 return isl_change_none
;
2919 list
= set_up_substitutions(info
[i
].bmap
, info
[j
].bmap
, hull_j
);
2921 return isl_change_error
;
2922 if (isl_aff_list_n_aff(list
) < n_div_i
)
2923 change
= isl_change_none
;
2925 change
= coalesce_with_subs(i
, j
, info
, list
);
2927 isl_aff_list_free(list
);
2931 isl_basic_map_free(hull_j
);
2932 return isl_change_error
;
2935 /* Check if we can coalesce basic maps "i" and "j" after copying
2936 * those extra integer divisions in one of the basic maps that can
2937 * be simplified away using the extra equalities in the other basic map.
2938 * We require all divs to be known in both basic maps.
2939 * Furthermore, to simplify the comparison of div expressions,
2940 * we do not allow any nested integer divisions.
2942 static enum isl_change
check_coalesce_eq(int i
, int j
,
2943 struct isl_coalesce_info
*info
)
2946 enum isl_change change
;
2948 known
= isl_basic_map_divs_known(info
[i
].bmap
);
2949 if (known
< 0 || !known
)
2950 return known
< 0 ? isl_change_error
: isl_change_none
;
2951 known
= isl_basic_map_divs_known(info
[j
].bmap
);
2952 if (known
< 0 || !known
)
2953 return known
< 0 ? isl_change_error
: isl_change_none
;
2954 nested
= has_nested_div(info
[i
].bmap
);
2955 if (nested
< 0 || nested
)
2956 return nested
< 0 ? isl_change_error
: isl_change_none
;
2957 nested
= has_nested_div(info
[j
].bmap
);
2958 if (nested
< 0 || nested
)
2959 return nested
< 0 ? isl_change_error
: isl_change_none
;
2961 change
= check_coalesce_into_eq(i
, j
, info
);
2962 if (change
!= isl_change_none
)
2964 change
= check_coalesce_into_eq(j
, i
, info
);
2965 if (change
!= isl_change_none
)
2966 return invert_change(change
);
2968 return isl_change_none
;
2971 /* Check if the union of the given pair of basic maps
2972 * can be represented by a single basic map.
2973 * If so, replace the pair by the single basic map and return
2974 * isl_change_drop_first, isl_change_drop_second or isl_change_fuse.
2975 * Otherwise, return isl_change_none.
2977 * We first check if the two basic maps live in the same local space,
2978 * after aligning the divs that differ by only an integer constant.
2979 * If so, we do the complete check. Otherwise, we check if they have
2980 * the same number of integer divisions and can be coalesced, if one is
2981 * an obvious subset of the other or if the extra integer divisions
2982 * of one basic map can be simplified away using the extra equalities
2983 * of the other basic map.
2985 static enum isl_change
coalesce_pair(int i
, int j
,
2986 struct isl_coalesce_info
*info
)
2989 enum isl_change change
;
2991 if (harmonize_divs(&info
[i
], &info
[j
]) < 0)
2992 return isl_change_error
;
2993 same
= same_divs(info
[i
].bmap
, info
[j
].bmap
);
2995 return isl_change_error
;
2997 return coalesce_local_pair(i
, j
, info
);
2999 if (info
[i
].bmap
->n_div
== info
[j
].bmap
->n_div
) {
3000 change
= coalesce_local_pair(i
, j
, info
);
3001 if (change
!= isl_change_none
)
3005 change
= coalesce_divs(i
, j
, info
);
3006 if (change
!= isl_change_none
)
3009 return check_coalesce_eq(i
, j
, info
);
3012 /* Return the maximum of "a" and "b".
3014 static int isl_max(int a
, int b
)
3016 return a
> b
? a
: b
;
3019 /* Pairwise coalesce the basic maps in the range [start1, end1[ of "info"
3020 * with those in the range [start2, end2[, skipping basic maps
3021 * that have been removed (either before or within this function).
3023 * For each basic map i in the first range, we check if it can be coalesced
3024 * with respect to any previously considered basic map j in the second range.
3025 * If i gets dropped (because it was a subset of some j), then
3026 * we can move on to the next basic map.
3027 * If j gets dropped, we need to continue checking against the other
3028 * previously considered basic maps.
3029 * If the two basic maps got fused, then we recheck the fused basic map
3030 * against the previously considered basic maps, starting at i + 1
3031 * (even if start2 is greater than i + 1).
3033 static int coalesce_range(isl_ctx
*ctx
, struct isl_coalesce_info
*info
,
3034 int start1
, int end1
, int start2
, int end2
)
3038 for (i
= end1
- 1; i
>= start1
; --i
) {
3039 if (info
[i
].removed
)
3041 for (j
= isl_max(i
+ 1, start2
); j
< end2
; ++j
) {
3042 enum isl_change changed
;
3044 if (info
[j
].removed
)
3046 if (info
[i
].removed
)
3047 isl_die(ctx
, isl_error_internal
,
3048 "basic map unexpectedly removed",
3050 changed
= coalesce_pair(i
, j
, info
);
3052 case isl_change_error
:
3054 case isl_change_none
:
3055 case isl_change_drop_second
:
3057 case isl_change_drop_first
:
3060 case isl_change_fuse
:
3070 /* Pairwise coalesce the basic maps described by the "n" elements of "info".
3072 * We consider groups of basic maps that live in the same apparent
3073 * affine hull and we first coalesce within such a group before we
3074 * coalesce the elements in the group with elements of previously
3075 * considered groups. If a fuse happens during the second phase,
3076 * then we also reconsider the elements within the group.
3078 static int coalesce(isl_ctx
*ctx
, int n
, struct isl_coalesce_info
*info
)
3082 for (end
= n
; end
> 0; end
= start
) {
3084 while (start
>= 1 &&
3085 info
[start
- 1].hull_hash
== info
[start
].hull_hash
)
3087 if (coalesce_range(ctx
, info
, start
, end
, start
, end
) < 0)
3089 if (coalesce_range(ctx
, info
, start
, end
, end
, n
) < 0)
3096 /* Update the basic maps in "map" based on the information in "info".
3097 * In particular, remove the basic maps that have been marked removed and
3098 * update the others based on the information in the corresponding tableau.
3099 * Since we detected implicit equalities without calling
3100 * isl_basic_map_gauss, we need to do it now.
3101 * Also call isl_basic_map_simplify if we may have lost the definition
3102 * of one or more integer divisions.
3104 static __isl_give isl_map
*update_basic_maps(__isl_take isl_map
*map
,
3105 int n
, struct isl_coalesce_info
*info
)
3112 for (i
= n
- 1; i
>= 0; --i
) {
3113 if (info
[i
].removed
) {
3114 isl_basic_map_free(map
->p
[i
]);
3115 if (i
!= map
->n
- 1)
3116 map
->p
[i
] = map
->p
[map
->n
- 1];
3121 info
[i
].bmap
= isl_basic_map_update_from_tab(info
[i
].bmap
,
3123 info
[i
].bmap
= isl_basic_map_gauss(info
[i
].bmap
, NULL
);
3124 if (info
[i
].simplify
)
3125 info
[i
].bmap
= isl_basic_map_simplify(info
[i
].bmap
);
3126 info
[i
].bmap
= isl_basic_map_finalize(info
[i
].bmap
);
3128 return isl_map_free(map
);
3129 ISL_F_SET(info
[i
].bmap
, ISL_BASIC_MAP_NO_IMPLICIT
);
3130 ISL_F_SET(info
[i
].bmap
, ISL_BASIC_MAP_NO_REDUNDANT
);
3131 isl_basic_map_free(map
->p
[i
]);
3132 map
->p
[i
] = info
[i
].bmap
;
3133 info
[i
].bmap
= NULL
;
3139 /* For each pair of basic maps in the map, check if the union of the two
3140 * can be represented by a single basic map.
3141 * If so, replace the pair by the single basic map and start over.
3143 * We factor out any (hidden) common factor from the constraint
3144 * coefficients to improve the detection of adjacent constraints.
3146 * Since we are constructing the tableaus of the basic maps anyway,
3147 * we exploit them to detect implicit equalities and redundant constraints.
3148 * This also helps the coalescing as it can ignore the redundant constraints.
3149 * In order to avoid confusion, we make all implicit equalities explicit
3150 * in the basic maps. We don't call isl_basic_map_gauss, though,
3151 * as that may affect the number of constraints.
3152 * This means that we have to call isl_basic_map_gauss at the end
3153 * of the computation (in update_basic_maps) to ensure that
3154 * the basic maps are not left in an unexpected state.
3155 * For each basic map, we also compute the hash of the apparent affine hull
3156 * for use in coalesce.
3158 struct isl_map
*isl_map_coalesce(struct isl_map
*map
)
3163 struct isl_coalesce_info
*info
= NULL
;
3165 map
= isl_map_remove_empty_parts(map
);
3172 ctx
= isl_map_get_ctx(map
);
3173 map
= isl_map_sort_divs(map
);
3174 map
= isl_map_cow(map
);
3181 info
= isl_calloc_array(map
->ctx
, struct isl_coalesce_info
, n
);
3185 for (i
= 0; i
< map
->n
; ++i
) {
3186 map
->p
[i
] = isl_basic_map_reduce_coefficients(map
->p
[i
]);
3189 info
[i
].bmap
= isl_basic_map_copy(map
->p
[i
]);
3190 info
[i
].tab
= isl_tab_from_basic_map(info
[i
].bmap
, 0);
3193 if (!ISL_F_ISSET(info
[i
].bmap
, ISL_BASIC_MAP_NO_IMPLICIT
))
3194 if (isl_tab_detect_implicit_equalities(info
[i
].tab
) < 0)
3196 info
[i
].bmap
= isl_tab_make_equalities_explicit(info
[i
].tab
,
3200 if (!ISL_F_ISSET(info
[i
].bmap
, ISL_BASIC_MAP_NO_REDUNDANT
))
3201 if (isl_tab_detect_redundant(info
[i
].tab
) < 0)
3203 if (coalesce_info_set_hull_hash(&info
[i
]) < 0)
3206 for (i
= map
->n
- 1; i
>= 0; --i
)
3207 if (info
[i
].tab
->empty
)
3210 if (coalesce(ctx
, n
, info
) < 0)
3213 map
= update_basic_maps(map
, n
, info
);
3215 clear_coalesce_info(n
, info
);
3219 clear_coalesce_info(n
, info
);
3224 /* For each pair of basic sets in the set, check if the union of the two
3225 * can be represented by a single basic set.
3226 * If so, replace the pair by the single basic set and start over.
3228 struct isl_set
*isl_set_coalesce(struct isl_set
*set
)
3230 return set_from_map(isl_map_coalesce(set_to_map(set
)));