2 * Copyright 2008-2009 Katholieke Universiteit Leuven
4 * Use of this software is governed by the GNU LGPLv2.1 license
6 * Written by Sven Verdoolaege, K.U.Leuven, Departement
7 * Computerwetenschappen, Celestijnenlaan 200A, B-3001 Leuven, Belgium
10 #include "isl_equalities.h"
12 #include "isl_map_private.h"
16 static void swap_equality(struct isl_basic_map
*bmap
, int a
, int b
)
18 isl_int
*t
= bmap
->eq
[a
];
19 bmap
->eq
[a
] = bmap
->eq
[b
];
23 static void swap_inequality(struct isl_basic_map
*bmap
, int a
, int b
)
26 isl_int
*t
= bmap
->ineq
[a
];
27 bmap
->ineq
[a
] = bmap
->ineq
[b
];
32 static void set_swap_inequality(struct isl_basic_set
*bset
, int a
, int b
)
34 swap_inequality((struct isl_basic_map
*)bset
, a
, b
);
37 static void constraint_drop_vars(isl_int
*c
, unsigned n
, unsigned rem
)
39 isl_seq_cpy(c
, c
+ n
, rem
);
40 isl_seq_clr(c
+ rem
, n
);
43 /* Drop n dimensions starting at first.
45 * In principle, this frees up some extra variables as the number
46 * of columns remains constant, but we would have to extend
47 * the div array too as the number of rows in this array is assumed
48 * to be equal to extra.
50 struct isl_basic_set
*isl_basic_set_drop_dims(
51 struct isl_basic_set
*bset
, unsigned first
, unsigned n
)
58 isl_assert(bset
->ctx
, first
+ n
<= bset
->dim
->n_out
, goto error
);
63 bset
= isl_basic_set_cow(bset
);
67 for (i
= 0; i
< bset
->n_eq
; ++i
)
68 constraint_drop_vars(bset
->eq
[i
]+1+bset
->dim
->nparam
+first
, n
,
69 (bset
->dim
->n_out
-first
-n
)+bset
->extra
);
71 for (i
= 0; i
< bset
->n_ineq
; ++i
)
72 constraint_drop_vars(bset
->ineq
[i
]+1+bset
->dim
->nparam
+first
, n
,
73 (bset
->dim
->n_out
-first
-n
)+bset
->extra
);
75 for (i
= 0; i
< bset
->n_div
; ++i
)
76 constraint_drop_vars(bset
->div
[i
]+1+1+bset
->dim
->nparam
+first
, n
,
77 (bset
->dim
->n_out
-first
-n
)+bset
->extra
);
79 bset
->dim
= isl_dim_drop_outputs(bset
->dim
, first
, n
);
83 ISL_F_CLR(bset
, ISL_BASIC_SET_NORMALIZED
);
84 bset
= isl_basic_set_simplify(bset
);
85 return isl_basic_set_finalize(bset
);
87 isl_basic_set_free(bset
);
91 struct isl_set
*isl_set_drop_dims(
92 struct isl_set
*set
, unsigned first
, unsigned n
)
99 isl_assert(set
->ctx
, first
+ n
<= set
->dim
->n_out
, goto error
);
103 set
= isl_set_cow(set
);
106 set
->dim
= isl_dim_drop_outputs(set
->dim
, first
, n
);
110 for (i
= 0; i
< set
->n
; ++i
) {
111 set
->p
[i
] = isl_basic_set_drop_dims(set
->p
[i
], first
, n
);
116 ISL_F_CLR(set
, ISL_SET_NORMALIZED
);
123 /* Move "n" divs starting at "first" to the end of the list of divs.
125 static struct isl_basic_map
*move_divs_last(struct isl_basic_map
*bmap
,
126 unsigned first
, unsigned n
)
131 if (first
+ n
== bmap
->n_div
)
134 div
= isl_alloc_array(bmap
->ctx
, isl_int
*, n
);
137 for (i
= 0; i
< n
; ++i
)
138 div
[i
] = bmap
->div
[first
+ i
];
139 for (i
= 0; i
< bmap
->n_div
- first
- n
; ++i
)
140 bmap
->div
[first
+ i
] = bmap
->div
[first
+ n
+ i
];
141 for (i
= 0; i
< n
; ++i
)
142 bmap
->div
[bmap
->n_div
- n
+ i
] = div
[i
];
146 isl_basic_map_free(bmap
);
150 /* Drop "n" dimensions of type "type" starting at "first".
152 * In principle, this frees up some extra variables as the number
153 * of columns remains constant, but we would have to extend
154 * the div array too as the number of rows in this array is assumed
155 * to be equal to extra.
157 struct isl_basic_map
*isl_basic_map_drop(struct isl_basic_map
*bmap
,
158 enum isl_dim_type type
, unsigned first
, unsigned n
)
168 dim
= isl_basic_map_dim(bmap
, type
);
169 isl_assert(bmap
->ctx
, first
+ n
<= dim
, goto error
);
174 bmap
= isl_basic_map_cow(bmap
);
178 offset
= isl_basic_map_offset(bmap
, type
) + first
;
179 left
= isl_basic_map_total_dim(bmap
) - (offset
- 1) - n
;
180 for (i
= 0; i
< bmap
->n_eq
; ++i
)
181 constraint_drop_vars(bmap
->eq
[i
]+offset
, n
, left
);
183 for (i
= 0; i
< bmap
->n_ineq
; ++i
)
184 constraint_drop_vars(bmap
->ineq
[i
]+offset
, n
, left
);
186 for (i
= 0; i
< bmap
->n_div
; ++i
)
187 constraint_drop_vars(bmap
->div
[i
]+1+offset
, n
, left
);
189 if (type
== isl_dim_div
) {
190 bmap
= move_divs_last(bmap
, first
, n
);
193 isl_basic_map_free_div(bmap
, n
);
195 bmap
->dim
= isl_dim_drop(bmap
->dim
, type
, first
, n
);
199 ISL_F_CLR(bmap
, ISL_BASIC_MAP_NORMALIZED
);
200 bmap
= isl_basic_map_simplify(bmap
);
201 return isl_basic_map_finalize(bmap
);
203 isl_basic_map_free(bmap
);
207 __isl_give isl_basic_set
*isl_basic_set_drop(__isl_take isl_basic_set
*bset
,
208 enum isl_dim_type type
, unsigned first
, unsigned n
)
210 return (isl_basic_set
*)isl_basic_map_drop((isl_basic_map
*)bset
,
214 struct isl_basic_map
*isl_basic_map_drop_inputs(
215 struct isl_basic_map
*bmap
, unsigned first
, unsigned n
)
217 return isl_basic_map_drop(bmap
, isl_dim_in
, first
, n
);
220 struct isl_map
*isl_map_drop(struct isl_map
*map
,
221 enum isl_dim_type type
, unsigned first
, unsigned n
)
228 isl_assert(map
->ctx
, first
+ n
<= isl_map_dim(map
, type
), goto error
);
232 map
= isl_map_cow(map
);
235 map
->dim
= isl_dim_drop(map
->dim
, type
, first
, n
);
239 for (i
= 0; i
< map
->n
; ++i
) {
240 map
->p
[i
] = isl_basic_map_drop(map
->p
[i
], type
, first
, n
);
244 ISL_F_CLR(map
, ISL_MAP_NORMALIZED
);
252 struct isl_set
*isl_set_drop(struct isl_set
*set
,
253 enum isl_dim_type type
, unsigned first
, unsigned n
)
255 return (isl_set
*)isl_map_drop((isl_map
*)set
, type
, first
, n
);
258 struct isl_map
*isl_map_drop_inputs(
259 struct isl_map
*map
, unsigned first
, unsigned n
)
261 return isl_map_drop(map
, isl_dim_in
, first
, n
);
265 * We don't cow, as the div is assumed to be redundant.
267 static struct isl_basic_map
*isl_basic_map_drop_div(
268 struct isl_basic_map
*bmap
, unsigned div
)
276 pos
= 1 + isl_dim_total(bmap
->dim
) + div
;
278 isl_assert(bmap
->ctx
, div
< bmap
->n_div
, goto error
);
280 for (i
= 0; i
< bmap
->n_eq
; ++i
)
281 constraint_drop_vars(bmap
->eq
[i
]+pos
, 1, bmap
->extra
-div
-1);
283 for (i
= 0; i
< bmap
->n_ineq
; ++i
) {
284 if (!isl_int_is_zero(bmap
->ineq
[i
][pos
])) {
285 isl_basic_map_drop_inequality(bmap
, i
);
289 constraint_drop_vars(bmap
->ineq
[i
]+pos
, 1, bmap
->extra
-div
-1);
292 for (i
= 0; i
< bmap
->n_div
; ++i
)
293 constraint_drop_vars(bmap
->div
[i
]+1+pos
, 1, bmap
->extra
-div
-1);
295 if (div
!= bmap
->n_div
- 1) {
297 isl_int
*t
= bmap
->div
[div
];
299 for (j
= div
; j
< bmap
->n_div
- 1; ++j
)
300 bmap
->div
[j
] = bmap
->div
[j
+1];
302 bmap
->div
[bmap
->n_div
- 1] = t
;
304 ISL_F_CLR(bmap
, ISL_BASIC_MAP_NORMALIZED
);
305 isl_basic_map_free_div(bmap
, 1);
309 isl_basic_map_free(bmap
);
313 struct isl_basic_map
*isl_basic_map_normalize_constraints(
314 struct isl_basic_map
*bmap
)
318 unsigned total
= isl_basic_map_total_dim(bmap
);
324 for (i
= bmap
->n_eq
- 1; i
>= 0; --i
) {
325 isl_seq_gcd(bmap
->eq
[i
]+1, total
, &gcd
);
326 if (isl_int_is_zero(gcd
)) {
327 if (!isl_int_is_zero(bmap
->eq
[i
][0])) {
328 bmap
= isl_basic_map_set_to_empty(bmap
);
331 isl_basic_map_drop_equality(bmap
, i
);
334 if (ISL_F_ISSET(bmap
, ISL_BASIC_MAP_RATIONAL
))
335 isl_int_gcd(gcd
, gcd
, bmap
->eq
[i
][0]);
336 if (isl_int_is_one(gcd
))
338 if (!isl_int_is_divisible_by(bmap
->eq
[i
][0], gcd
)) {
339 bmap
= isl_basic_map_set_to_empty(bmap
);
342 isl_seq_scale_down(bmap
->eq
[i
], bmap
->eq
[i
], gcd
, 1+total
);
345 for (i
= bmap
->n_ineq
- 1; i
>= 0; --i
) {
346 isl_seq_gcd(bmap
->ineq
[i
]+1, total
, &gcd
);
347 if (isl_int_is_zero(gcd
)) {
348 if (isl_int_is_neg(bmap
->ineq
[i
][0])) {
349 bmap
= isl_basic_map_set_to_empty(bmap
);
352 isl_basic_map_drop_inequality(bmap
, i
);
355 if (ISL_F_ISSET(bmap
, ISL_BASIC_MAP_RATIONAL
))
356 isl_int_gcd(gcd
, gcd
, bmap
->ineq
[i
][0]);
357 if (isl_int_is_one(gcd
))
359 isl_int_fdiv_q(bmap
->ineq
[i
][0], bmap
->ineq
[i
][0], gcd
);
360 isl_seq_scale_down(bmap
->ineq
[i
]+1, bmap
->ineq
[i
]+1, gcd
, total
);
367 struct isl_basic_set
*isl_basic_set_normalize_constraints(
368 struct isl_basic_set
*bset
)
370 return (struct isl_basic_set
*)isl_basic_map_normalize_constraints(
371 (struct isl_basic_map
*)bset
);
374 /* Assumes divs have been ordered if keep_divs is set.
376 static void eliminate_var_using_equality(struct isl_basic_map
*bmap
,
377 unsigned pos
, isl_int
*eq
, int keep_divs
, int *progress
)
383 total
= isl_basic_map_total_dim(bmap
);
384 last_div
= isl_seq_last_non_zero(eq
+ 1 + isl_dim_total(bmap
->dim
),
386 for (k
= 0; k
< bmap
->n_eq
; ++k
) {
387 if (bmap
->eq
[k
] == eq
)
389 if (isl_int_is_zero(bmap
->eq
[k
][1+pos
]))
393 isl_seq_elim(bmap
->eq
[k
], eq
, 1+pos
, 1+total
, NULL
);
396 for (k
= 0; k
< bmap
->n_ineq
; ++k
) {
397 if (isl_int_is_zero(bmap
->ineq
[k
][1+pos
]))
401 isl_seq_elim(bmap
->ineq
[k
], eq
, 1+pos
, 1+total
, NULL
);
402 ISL_F_CLR(bmap
, ISL_BASIC_MAP_NORMALIZED
);
405 for (k
= 0; k
< bmap
->n_div
; ++k
) {
406 if (isl_int_is_zero(bmap
->div
[k
][0]))
408 if (isl_int_is_zero(bmap
->div
[k
][1+1+pos
]))
412 /* We need to be careful about circular definitions,
413 * so for now we just remove the definition of div k
414 * if the equality contains any divs.
415 * If keep_divs is set, then the divs have been ordered
416 * and we can keep the definition as long as the result
419 if (last_div
== -1 || (keep_divs
&& last_div
< k
))
420 isl_seq_elim(bmap
->div
[k
]+1, eq
,
421 1+pos
, 1+total
, &bmap
->div
[k
][0]);
423 isl_seq_clr(bmap
->div
[k
], 1 + total
);
424 ISL_F_CLR(bmap
, ISL_BASIC_MAP_NORMALIZED
);
428 /* Assumes divs have been ordered if keep_divs is set.
430 static void eliminate_div(struct isl_basic_map
*bmap
, isl_int
*eq
,
431 unsigned div
, int keep_divs
)
433 unsigned pos
= isl_dim_total(bmap
->dim
) + div
;
435 eliminate_var_using_equality(bmap
, pos
, eq
, keep_divs
, NULL
);
437 isl_basic_map_drop_div(bmap
, div
);
440 /* Check if elimination of div "div" using equality "eq" would not
441 * result in a div depending on a later div.
443 static int ok_to_eliminate_div(struct isl_basic_map
*bmap
, isl_int
*eq
,
448 unsigned pos
= isl_dim_total(bmap
->dim
) + div
;
450 last_div
= isl_seq_last_non_zero(eq
+ 1 + isl_dim_total(bmap
->dim
),
452 if (last_div
< 0 || last_div
<= div
)
455 for (k
= 0; k
<= last_div
; ++k
) {
456 if (isl_int_is_zero(bmap
->div
[k
][0]))
458 if (!isl_int_is_zero(bmap
->div
[k
][1 + 1 + pos
]))
465 /* Elimininate divs based on equalities
467 static struct isl_basic_map
*eliminate_divs_eq(
468 struct isl_basic_map
*bmap
, int *progress
)
475 bmap
= isl_basic_map_order_divs(bmap
);
480 off
= 1 + isl_dim_total(bmap
->dim
);
482 for (d
= bmap
->n_div
- 1; d
>= 0 ; --d
) {
483 for (i
= 0; i
< bmap
->n_eq
; ++i
) {
484 if (!isl_int_is_one(bmap
->eq
[i
][off
+ d
]) &&
485 !isl_int_is_negone(bmap
->eq
[i
][off
+ d
]))
487 if (!ok_to_eliminate_div(bmap
, bmap
->eq
[i
], d
))
491 eliminate_div(bmap
, bmap
->eq
[i
], d
, 1);
492 isl_basic_map_drop_equality(bmap
, i
);
497 return eliminate_divs_eq(bmap
, progress
);
501 /* Elimininate divs based on inequalities
503 static struct isl_basic_map
*eliminate_divs_ineq(
504 struct isl_basic_map
*bmap
, int *progress
)
515 off
= 1 + isl_dim_total(bmap
->dim
);
517 for (d
= bmap
->n_div
- 1; d
>= 0 ; --d
) {
518 for (i
= 0; i
< bmap
->n_eq
; ++i
)
519 if (!isl_int_is_zero(bmap
->eq
[i
][off
+ d
]))
523 for (i
= 0; i
< bmap
->n_ineq
; ++i
)
524 if (isl_int_abs_gt(bmap
->ineq
[i
][off
+ d
], ctx
->one
))
526 if (i
< bmap
->n_ineq
)
529 bmap
= isl_basic_map_eliminate_vars(bmap
, (off
-1)+d
, 1);
530 if (!bmap
|| ISL_F_ISSET(bmap
, ISL_BASIC_MAP_EMPTY
))
532 bmap
= isl_basic_map_drop_div(bmap
, d
);
539 struct isl_basic_map
*isl_basic_map_gauss(
540 struct isl_basic_map
*bmap
, int *progress
)
548 bmap
= isl_basic_map_order_divs(bmap
);
553 total
= isl_basic_map_total_dim(bmap
);
554 total_var
= total
- bmap
->n_div
;
556 last_var
= total
- 1;
557 for (done
= 0; done
< bmap
->n_eq
; ++done
) {
558 for (; last_var
>= 0; --last_var
) {
559 for (k
= done
; k
< bmap
->n_eq
; ++k
)
560 if (!isl_int_is_zero(bmap
->eq
[k
][1+last_var
]))
568 swap_equality(bmap
, k
, done
);
569 if (isl_int_is_neg(bmap
->eq
[done
][1+last_var
]))
570 isl_seq_neg(bmap
->eq
[done
], bmap
->eq
[done
], 1+total
);
572 eliminate_var_using_equality(bmap
, last_var
, bmap
->eq
[done
], 1,
575 if (last_var
>= total_var
&&
576 isl_int_is_zero(bmap
->div
[last_var
- total_var
][0])) {
577 unsigned div
= last_var
- total_var
;
578 isl_seq_neg(bmap
->div
[div
]+1, bmap
->eq
[done
], 1+total
);
579 isl_int_set_si(bmap
->div
[div
][1+1+last_var
], 0);
580 isl_int_set(bmap
->div
[div
][0],
581 bmap
->eq
[done
][1+last_var
]);
582 ISL_F_CLR(bmap
, ISL_BASIC_MAP_NORMALIZED
);
585 if (done
== bmap
->n_eq
)
587 for (k
= done
; k
< bmap
->n_eq
; ++k
) {
588 if (isl_int_is_zero(bmap
->eq
[k
][0]))
590 return isl_basic_map_set_to_empty(bmap
);
592 isl_basic_map_free_equality(bmap
, bmap
->n_eq
-done
);
596 struct isl_basic_set
*isl_basic_set_gauss(
597 struct isl_basic_set
*bset
, int *progress
)
599 return (struct isl_basic_set
*)isl_basic_map_gauss(
600 (struct isl_basic_map
*)bset
, progress
);
604 static unsigned int round_up(unsigned int v
)
615 static int hash_index(isl_int
***index
, unsigned int size
, int bits
,
616 struct isl_basic_map
*bmap
, int k
)
619 unsigned total
= isl_basic_map_total_dim(bmap
);
620 uint32_t hash
= isl_seq_get_hash_bits(bmap
->ineq
[k
]+1, total
, bits
);
621 for (h
= hash
; index
[h
]; h
= (h
+1) % size
)
622 if (&bmap
->ineq
[k
] != index
[h
] &&
623 isl_seq_eq(bmap
->ineq
[k
]+1, index
[h
][0]+1, total
))
628 static int set_hash_index(isl_int
***index
, unsigned int size
, int bits
,
629 struct isl_basic_set
*bset
, int k
)
631 return hash_index(index
, size
, bits
, (struct isl_basic_map
*)bset
, k
);
634 /* If we can eliminate more than one div, then we need to make
635 * sure we do it from last div to first div, in order not to
636 * change the position of the other divs that still need to
639 static struct isl_basic_map
*remove_duplicate_divs(
640 struct isl_basic_map
*bmap
, int *progress
)
648 unsigned total_var
= isl_dim_total(bmap
->dim
);
649 unsigned total
= total_var
+ bmap
->n_div
;
652 if (bmap
->n_div
<= 1)
656 for (k
= bmap
->n_div
- 1; k
>= 0; --k
)
657 if (!isl_int_is_zero(bmap
->div
[k
][0]))
662 elim_for
= isl_calloc_array(ctx
, int, bmap
->n_div
);
663 size
= round_up(4 * bmap
->n_div
/ 3 - 1);
664 bits
= ffs(size
) - 1;
665 index
= isl_calloc_array(ctx
, int, size
);
668 eq
= isl_blk_alloc(ctx
, 1+total
);
669 if (isl_blk_is_error(eq
))
672 isl_seq_clr(eq
.data
, 1+total
);
673 index
[isl_seq_get_hash_bits(bmap
->div
[k
], 2+total
, bits
)] = k
+ 1;
674 for (--k
; k
>= 0; --k
) {
677 if (isl_int_is_zero(bmap
->div
[k
][0]))
680 hash
= isl_seq_get_hash_bits(bmap
->div
[k
], 2+total
, bits
);
681 for (h
= hash
; index
[h
]; h
= (h
+1) % size
)
682 if (isl_seq_eq(bmap
->div
[k
],
683 bmap
->div
[index
[h
]-1], 2+total
))
692 for (l
= bmap
->n_div
- 1; l
>= 0; --l
) {
696 isl_int_set_si(eq
.data
[1+total_var
+k
], -1);
697 isl_int_set_si(eq
.data
[1+total_var
+l
], 1);
698 eliminate_div(bmap
, eq
.data
, l
, 0);
699 isl_int_set_si(eq
.data
[1+total_var
+k
], 0);
700 isl_int_set_si(eq
.data
[1+total_var
+l
], 0);
703 isl_blk_free(ctx
, eq
);
710 static int n_pure_div_eq(struct isl_basic_map
*bmap
)
715 total
= isl_dim_total(bmap
->dim
);
716 for (i
= 0, j
= bmap
->n_div
-1; i
< bmap
->n_eq
; ++i
) {
717 while (j
>= 0 && isl_int_is_zero(bmap
->eq
[i
][1 + total
+ j
]))
721 if (isl_seq_first_non_zero(bmap
->eq
[i
] + 1 + total
, j
) != -1)
727 /* Normalize divs that appear in equalities.
729 * In particular, we assume that bmap contains some equalities
734 * and we want to replace the set of e_i by a minimal set and
735 * such that the new e_i have a canonical representation in terms
737 * If any of the equalities involves more than one divs, then
738 * we currently simply bail out.
740 * Let us first additionally assume that all equalities involve
741 * a div. The equalities then express modulo constraints on the
742 * remaining variables and we can use "parameter compression"
743 * to find a minimal set of constraints. The result is a transformation
745 * x = T(x') = x_0 + G x'
747 * with G a lower-triangular matrix with all elements below the diagonal
748 * non-negative and smaller than the diagonal element on the same row.
749 * We first normalize x_0 by making the same property hold in the affine
751 * The rows i of G with a 1 on the diagonal do not impose any modulo
752 * constraint and simply express x_i = x'_i.
753 * For each of the remaining rows i, we introduce a div and a corresponding
754 * equality. In particular
756 * g_ii e_j = x_i - g_i(x')
758 * where each x'_k is replaced either by x_k (if g_kk = 1) or the
759 * corresponding div (if g_kk != 1).
761 * If there are any equalities not involving any div, then we
762 * first apply a variable compression on the variables x:
764 * x = C x'' x'' = C_2 x
766 * and perform the above parameter compression on A C instead of on A.
767 * The resulting compression is then of the form
769 * x'' = T(x') = x_0 + G x'
771 * and in constructing the new divs and the corresponding equalities,
772 * we have to replace each x'', i.e., the x'_k with (g_kk = 1),
773 * by the corresponding row from C_2.
775 static struct isl_basic_map
*normalize_divs(
776 struct isl_basic_map
*bmap
, int *progress
)
783 struct isl_mat
*T
= NULL
;
784 struct isl_mat
*C
= NULL
;
785 struct isl_mat
*C2
= NULL
;
793 if (bmap
->n_div
== 0)
799 if (ISL_F_ISSET(bmap
, ISL_BASIC_MAP_NORMALIZED_DIVS
))
802 total
= isl_dim_total(bmap
->dim
);
803 div_eq
= n_pure_div_eq(bmap
);
807 if (div_eq
< bmap
->n_eq
) {
808 B
= isl_mat_sub_alloc(bmap
->ctx
, bmap
->eq
, div_eq
,
809 bmap
->n_eq
- div_eq
, 0, 1 + total
);
810 C
= isl_mat_variable_compression(B
, &C2
);
814 bmap
= isl_basic_map_set_to_empty(bmap
);
821 d
= isl_vec_alloc(bmap
->ctx
, div_eq
);
824 for (i
= 0, j
= bmap
->n_div
-1; i
< div_eq
; ++i
) {
825 while (j
>= 0 && isl_int_is_zero(bmap
->eq
[i
][1 + total
+ j
]))
827 isl_int_set(d
->block
.data
[i
], bmap
->eq
[i
][1 + total
+ j
]);
829 B
= isl_mat_sub_alloc(bmap
->ctx
, bmap
->eq
, 0, div_eq
, 0, 1 + total
);
832 B
= isl_mat_product(B
, C
);
836 T
= isl_mat_parameter_compression(B
, d
);
840 bmap
= isl_basic_map_set_to_empty(bmap
);
846 for (i
= 0; i
< T
->n_row
- 1; ++i
) {
847 isl_int_fdiv_q(v
, T
->row
[1 + i
][0], T
->row
[1 + i
][1 + i
]);
848 if (isl_int_is_zero(v
))
850 isl_mat_col_submul(T
, 0, v
, 1 + i
);
853 pos
= isl_alloc_array(bmap
->ctx
, int, T
->n_row
);
854 /* We have to be careful because dropping equalities may reorder them */
856 for (j
= bmap
->n_div
- 1; j
>= 0; --j
) {
857 for (i
= 0; i
< bmap
->n_eq
; ++i
)
858 if (!isl_int_is_zero(bmap
->eq
[i
][1 + total
+ j
]))
860 if (i
< bmap
->n_eq
) {
861 bmap
= isl_basic_map_drop_div(bmap
, j
);
862 isl_basic_map_drop_equality(bmap
, i
);
868 for (i
= 1; i
< T
->n_row
; ++i
) {
869 if (isl_int_is_one(T
->row
[i
][i
]))
874 if (needed
> dropped
) {
875 bmap
= isl_basic_map_extend_dim(bmap
, isl_dim_copy(bmap
->dim
),
880 for (i
= 1; i
< T
->n_row
; ++i
) {
881 if (isl_int_is_one(T
->row
[i
][i
]))
883 k
= isl_basic_map_alloc_div(bmap
);
884 pos
[i
] = 1 + total
+ k
;
885 isl_seq_clr(bmap
->div
[k
] + 1, 1 + total
+ bmap
->n_div
);
886 isl_int_set(bmap
->div
[k
][0], T
->row
[i
][i
]);
888 isl_seq_cpy(bmap
->div
[k
] + 1, C2
->row
[i
], 1 + total
);
890 isl_int_set_si(bmap
->div
[k
][1 + i
], 1);
891 for (j
= 0; j
< i
; ++j
) {
892 if (isl_int_is_zero(T
->row
[i
][j
]))
894 if (pos
[j
] < T
->n_row
&& C2
)
895 isl_seq_submul(bmap
->div
[k
] + 1, T
->row
[i
][j
],
896 C2
->row
[pos
[j
]], 1 + total
);
898 isl_int_neg(bmap
->div
[k
][1 + pos
[j
]],
901 j
= isl_basic_map_alloc_equality(bmap
);
902 isl_seq_neg(bmap
->eq
[j
], bmap
->div
[k
]+1, 1+total
+bmap
->n_div
);
903 isl_int_set(bmap
->eq
[j
][pos
[i
]], bmap
->div
[k
][0]);
912 ISL_F_SET(bmap
, ISL_BASIC_MAP_NORMALIZED_DIVS
);
922 static struct isl_basic_map
*set_div_from_lower_bound(
923 struct isl_basic_map
*bmap
, int div
, int ineq
)
925 unsigned total
= 1 + isl_dim_total(bmap
->dim
);
927 isl_seq_neg(bmap
->div
[div
] + 1, bmap
->ineq
[ineq
], total
+ bmap
->n_div
);
928 isl_int_set(bmap
->div
[div
][0], bmap
->ineq
[ineq
][total
+ div
]);
929 isl_int_add(bmap
->div
[div
][1], bmap
->div
[div
][1], bmap
->div
[div
][0]);
930 isl_int_sub_ui(bmap
->div
[div
][1], bmap
->div
[div
][1], 1);
931 isl_int_set_si(bmap
->div
[div
][1 + total
+ div
], 0);
936 /* Check whether it is ok to define a div based on an inequality.
937 * To avoid the introduction of circular definitions of divs, we
938 * do not allow such a definition if the resulting expression would refer to
939 * any other undefined divs or if any known div is defined in
940 * terms of the unknown div.
942 static int ok_to_set_div_from_bound(struct isl_basic_map
*bmap
,
946 unsigned total
= 1 + isl_dim_total(bmap
->dim
);
948 /* Not defined in terms of unknown divs */
949 for (j
= 0; j
< bmap
->n_div
; ++j
) {
952 if (isl_int_is_zero(bmap
->ineq
[ineq
][total
+ j
]))
954 if (isl_int_is_zero(bmap
->div
[j
][0]))
958 /* No other div defined in terms of this one => avoid loops */
959 for (j
= 0; j
< bmap
->n_div
; ++j
) {
962 if (isl_int_is_zero(bmap
->div
[j
][0]))
964 if (!isl_int_is_zero(bmap
->div
[j
][1 + total
+ div
]))
971 /* Given two constraints "k" and "l" that are opposite to each other,
972 * except for the constant term, check if we can use them
973 * to obtain an expression for one of the hitherto unknown divs.
974 * "sum" is the sum of the constant terms of the constraints.
975 * If this sum is strictly smaller than the coefficient of one
976 * of the divs, then this pair can be used define the div.
977 * To avoid the introduction of circular definitions of divs, we
978 * do not use the pair if the resulting expression would refer to
979 * any other undefined divs or if any known div is defined in
980 * terms of the unknown div.
982 static struct isl_basic_map
*check_for_div_constraints(
983 struct isl_basic_map
*bmap
, int k
, int l
, isl_int sum
, int *progress
)
986 unsigned total
= 1 + isl_dim_total(bmap
->dim
);
988 for (i
= 0; i
< bmap
->n_div
; ++i
) {
989 if (!isl_int_is_zero(bmap
->div
[i
][0]))
991 if (isl_int_is_zero(bmap
->ineq
[k
][total
+ i
]))
993 if (isl_int_abs_ge(sum
, bmap
->ineq
[k
][total
+ i
]))
995 if (!ok_to_set_div_from_bound(bmap
, i
, k
))
997 if (isl_int_is_pos(bmap
->ineq
[k
][total
+ i
]))
998 bmap
= set_div_from_lower_bound(bmap
, i
, k
);
1000 bmap
= set_div_from_lower_bound(bmap
, i
, l
);
1008 static struct isl_basic_map
*remove_duplicate_constraints(
1009 struct isl_basic_map
*bmap
, int *progress
)
1015 unsigned total
= isl_basic_map_total_dim(bmap
);
1018 if (bmap
->n_ineq
<= 1)
1021 size
= round_up(4 * (bmap
->n_ineq
+1) / 3 - 1);
1022 bits
= ffs(size
) - 1;
1023 index
= isl_calloc_array(ctx
, isl_int
**, size
);
1027 index
[isl_seq_get_hash_bits(bmap
->ineq
[0]+1, total
, bits
)] = &bmap
->ineq
[0];
1028 for (k
= 1; k
< bmap
->n_ineq
; ++k
) {
1029 h
= hash_index(index
, size
, bits
, bmap
, k
);
1031 index
[h
] = &bmap
->ineq
[k
];
1036 l
= index
[h
] - &bmap
->ineq
[0];
1037 if (isl_int_lt(bmap
->ineq
[k
][0], bmap
->ineq
[l
][0]))
1038 swap_inequality(bmap
, k
, l
);
1039 isl_basic_map_drop_inequality(bmap
, k
);
1043 for (k
= 0; k
< bmap
->n_ineq
-1; ++k
) {
1044 isl_seq_neg(bmap
->ineq
[k
]+1, bmap
->ineq
[k
]+1, total
);
1045 h
= hash_index(index
, size
, bits
, bmap
, k
);
1046 isl_seq_neg(bmap
->ineq
[k
]+1, bmap
->ineq
[k
]+1, total
);
1049 l
= index
[h
] - &bmap
->ineq
[0];
1050 isl_int_add(sum
, bmap
->ineq
[k
][0], bmap
->ineq
[l
][0]);
1051 if (isl_int_is_pos(sum
)) {
1052 bmap
= check_for_div_constraints(bmap
, k
, l
, sum
,
1056 if (isl_int_is_zero(sum
)) {
1057 /* We need to break out of the loop after these
1058 * changes since the contents of the hash
1059 * will no longer be valid.
1060 * Plus, we probably we want to regauss first.
1064 isl_basic_map_drop_inequality(bmap
, l
);
1065 isl_basic_map_inequality_to_equality(bmap
, k
);
1067 bmap
= isl_basic_map_set_to_empty(bmap
);
1077 struct isl_basic_map
*isl_basic_map_simplify(struct isl_basic_map
*bmap
)
1084 bmap
= isl_basic_map_normalize_constraints(bmap
);
1085 bmap
= remove_duplicate_divs(bmap
, &progress
);
1086 bmap
= eliminate_divs_eq(bmap
, &progress
);
1087 bmap
= eliminate_divs_ineq(bmap
, &progress
);
1088 bmap
= isl_basic_map_gauss(bmap
, &progress
);
1089 /* requires equalities in normal form */
1090 bmap
= normalize_divs(bmap
, &progress
);
1091 bmap
= remove_duplicate_constraints(bmap
, &progress
);
1096 struct isl_basic_set
*isl_basic_set_simplify(struct isl_basic_set
*bset
)
1098 return (struct isl_basic_set
*)
1099 isl_basic_map_simplify((struct isl_basic_map
*)bset
);
1103 /* If the only constraints a div d=floor(f/m)
1104 * appears in are its two defining constraints
1107 * -(f - (m - 1)) + m d >= 0
1109 * then it can safely be removed.
1111 static int div_is_redundant(struct isl_basic_map
*bmap
, int div
)
1114 unsigned pos
= 1 + isl_dim_total(bmap
->dim
) + div
;
1116 for (i
= 0; i
< bmap
->n_eq
; ++i
)
1117 if (!isl_int_is_zero(bmap
->eq
[i
][pos
]))
1120 for (i
= 0; i
< bmap
->n_ineq
; ++i
) {
1121 if (isl_int_is_zero(bmap
->ineq
[i
][pos
]))
1123 if (isl_int_eq(bmap
->ineq
[i
][pos
], bmap
->div
[div
][0])) {
1125 isl_int_sub(bmap
->div
[div
][1],
1126 bmap
->div
[div
][1], bmap
->div
[div
][0]);
1127 isl_int_add_ui(bmap
->div
[div
][1], bmap
->div
[div
][1], 1);
1128 neg
= isl_seq_is_neg(bmap
->ineq
[i
], bmap
->div
[div
]+1, pos
);
1129 isl_int_sub_ui(bmap
->div
[div
][1], bmap
->div
[div
][1], 1);
1130 isl_int_add(bmap
->div
[div
][1],
1131 bmap
->div
[div
][1], bmap
->div
[div
][0]);
1134 if (isl_seq_first_non_zero(bmap
->ineq
[i
]+pos
+1,
1135 bmap
->n_div
-div
-1) != -1)
1137 } else if (isl_int_abs_eq(bmap
->ineq
[i
][pos
], bmap
->div
[div
][0])) {
1138 if (!isl_seq_eq(bmap
->ineq
[i
], bmap
->div
[div
]+1, pos
))
1140 if (isl_seq_first_non_zero(bmap
->ineq
[i
]+pos
+1,
1141 bmap
->n_div
-div
-1) != -1)
1147 for (i
= 0; i
< bmap
->n_div
; ++i
)
1148 if (!isl_int_is_zero(bmap
->div
[i
][1+pos
]))
1155 * Remove divs that don't occur in any of the constraints or other divs.
1156 * These can arise when dropping some of the variables in a quast
1157 * returned by piplib.
1159 static struct isl_basic_map
*remove_redundant_divs(struct isl_basic_map
*bmap
)
1166 for (i
= bmap
->n_div
-1; i
>= 0; --i
) {
1167 if (!div_is_redundant(bmap
, i
))
1169 bmap
= isl_basic_map_drop_div(bmap
, i
);
1174 struct isl_basic_map
*isl_basic_map_finalize(struct isl_basic_map
*bmap
)
1176 bmap
= remove_redundant_divs(bmap
);
1179 ISL_F_SET(bmap
, ISL_BASIC_SET_FINAL
);
1183 struct isl_basic_set
*isl_basic_set_finalize(struct isl_basic_set
*bset
)
1185 return (struct isl_basic_set
*)
1186 isl_basic_map_finalize((struct isl_basic_map
*)bset
);
1189 struct isl_set
*isl_set_finalize(struct isl_set
*set
)
1195 for (i
= 0; i
< set
->n
; ++i
) {
1196 set
->p
[i
] = isl_basic_set_finalize(set
->p
[i
]);
1206 struct isl_map
*isl_map_finalize(struct isl_map
*map
)
1212 for (i
= 0; i
< map
->n
; ++i
) {
1213 map
->p
[i
] = isl_basic_map_finalize(map
->p
[i
]);
1217 ISL_F_CLR(map
, ISL_MAP_NORMALIZED
);
1225 /* Remove definition of any div that is defined in terms of the given variable.
1226 * The div itself is not removed. Functions such as
1227 * eliminate_divs_ineq depend on the other divs remaining in place.
1229 static struct isl_basic_map
*remove_dependent_vars(struct isl_basic_map
*bmap
,
1234 for (i
= 0; i
< bmap
->n_div
; ++i
) {
1235 if (isl_int_is_zero(bmap
->div
[i
][0]))
1237 if (isl_int_is_zero(bmap
->div
[i
][1+1+pos
]))
1239 isl_int_set_si(bmap
->div
[i
][0], 0);
1244 /* Eliminate the specified variables from the constraints using
1245 * Fourier-Motzkin. The variables themselves are not removed.
1247 struct isl_basic_map
*isl_basic_map_eliminate_vars(
1248 struct isl_basic_map
*bmap
, unsigned pos
, unsigned n
)
1258 total
= isl_basic_map_total_dim(bmap
);
1260 bmap
= isl_basic_map_cow(bmap
);
1261 for (d
= pos
+ n
- 1; d
>= 0 && d
>= pos
; --d
)
1262 bmap
= remove_dependent_vars(bmap
, d
);
1264 for (d
= pos
+ n
- 1;
1265 d
>= 0 && d
>= total
- bmap
->n_div
&& d
>= pos
; --d
)
1266 isl_seq_clr(bmap
->div
[d
-(total
-bmap
->n_div
)], 2+total
);
1267 for (d
= pos
+ n
- 1; d
>= 0 && d
>= pos
; --d
) {
1268 int n_lower
, n_upper
;
1271 for (i
= 0; i
< bmap
->n_eq
; ++i
) {
1272 if (isl_int_is_zero(bmap
->eq
[i
][1+d
]))
1274 eliminate_var_using_equality(bmap
, d
, bmap
->eq
[i
], 0, NULL
);
1275 isl_basic_map_drop_equality(bmap
, i
);
1282 for (i
= 0; i
< bmap
->n_ineq
; ++i
) {
1283 if (isl_int_is_pos(bmap
->ineq
[i
][1+d
]))
1285 else if (isl_int_is_neg(bmap
->ineq
[i
][1+d
]))
1288 bmap
= isl_basic_map_extend_constraints(bmap
,
1289 0, n_lower
* n_upper
);
1292 for (i
= bmap
->n_ineq
- 1; i
>= 0; --i
) {
1294 if (isl_int_is_zero(bmap
->ineq
[i
][1+d
]))
1297 for (j
= 0; j
< i
; ++j
) {
1298 if (isl_int_is_zero(bmap
->ineq
[j
][1+d
]))
1301 if (isl_int_sgn(bmap
->ineq
[i
][1+d
]) ==
1302 isl_int_sgn(bmap
->ineq
[j
][1+d
]))
1304 k
= isl_basic_map_alloc_inequality(bmap
);
1307 isl_seq_cpy(bmap
->ineq
[k
], bmap
->ineq
[i
],
1309 isl_seq_elim(bmap
->ineq
[k
], bmap
->ineq
[j
],
1310 1+d
, 1+total
, NULL
);
1312 isl_basic_map_drop_inequality(bmap
, i
);
1315 if (n_lower
> 0 && n_upper
> 0) {
1316 bmap
= isl_basic_map_normalize_constraints(bmap
);
1317 bmap
= remove_duplicate_constraints(bmap
, NULL
);
1318 bmap
= isl_basic_map_gauss(bmap
, NULL
);
1319 bmap
= isl_basic_map_convex_hull(bmap
);
1322 if (ISL_F_ISSET(bmap
, ISL_BASIC_MAP_EMPTY
))
1326 ISL_F_CLR(bmap
, ISL_BASIC_MAP_NORMALIZED
);
1329 isl_basic_map_free(bmap
);
1333 struct isl_basic_set
*isl_basic_set_eliminate_vars(
1334 struct isl_basic_set
*bset
, unsigned pos
, unsigned n
)
1336 return (struct isl_basic_set
*)isl_basic_map_eliminate_vars(
1337 (struct isl_basic_map
*)bset
, pos
, n
);
1340 /* Don't assume equalities are in order, because align_divs
1341 * may have changed the order of the divs.
1343 static void compute_elimination_index(struct isl_basic_map
*bmap
, int *elim
)
1348 total
= isl_dim_total(bmap
->dim
);
1349 for (d
= 0; d
< total
; ++d
)
1351 for (i
= 0; i
< bmap
->n_eq
; ++i
) {
1352 for (d
= total
- 1; d
>= 0; --d
) {
1353 if (isl_int_is_zero(bmap
->eq
[i
][1+d
]))
1361 static void set_compute_elimination_index(struct isl_basic_set
*bset
, int *elim
)
1363 compute_elimination_index((struct isl_basic_map
*)bset
, elim
);
1366 static int reduced_using_equalities(isl_int
*dst
, isl_int
*src
,
1367 struct isl_basic_map
*bmap
, int *elim
)
1373 total
= isl_dim_total(bmap
->dim
);
1374 for (d
= total
- 1; d
>= 0; --d
) {
1375 if (isl_int_is_zero(src
[1+d
]))
1380 isl_seq_cpy(dst
, src
, 1 + total
);
1383 isl_seq_elim(dst
, bmap
->eq
[elim
[d
]], 1 + d
, 1 + total
, NULL
);
1388 static int set_reduced_using_equalities(isl_int
*dst
, isl_int
*src
,
1389 struct isl_basic_set
*bset
, int *elim
)
1391 return reduced_using_equalities(dst
, src
,
1392 (struct isl_basic_map
*)bset
, elim
);
1395 static struct isl_basic_set
*isl_basic_set_reduce_using_equalities(
1396 struct isl_basic_set
*bset
, struct isl_basic_set
*context
)
1401 if (!bset
|| !context
)
1404 if (context
->n_eq
== 0) {
1405 isl_basic_set_free(context
);
1409 bset
= isl_basic_set_cow(bset
);
1413 elim
= isl_alloc_array(bset
->ctx
, int, isl_basic_set_n_dim(bset
));
1416 set_compute_elimination_index(context
, elim
);
1417 for (i
= 0; i
< bset
->n_eq
; ++i
)
1418 set_reduced_using_equalities(bset
->eq
[i
], bset
->eq
[i
],
1420 for (i
= 0; i
< bset
->n_ineq
; ++i
)
1421 set_reduced_using_equalities(bset
->ineq
[i
], bset
->ineq
[i
],
1423 isl_basic_set_free(context
);
1425 bset
= isl_basic_set_simplify(bset
);
1426 bset
= isl_basic_set_finalize(bset
);
1429 isl_basic_set_free(bset
);
1430 isl_basic_set_free(context
);
1434 static struct isl_basic_set
*remove_shifted_constraints(
1435 struct isl_basic_set
*bset
, struct isl_basic_set
*context
)
1445 size
= round_up(4 * (context
->n_ineq
+1) / 3 - 1);
1446 bits
= ffs(size
) - 1;
1447 index
= isl_calloc_array(ctx
, isl_int
**, size
);
1451 for (k
= 0; k
< context
->n_ineq
; ++k
) {
1452 h
= set_hash_index(index
, size
, bits
, context
, k
);
1453 index
[h
] = &context
->ineq
[k
];
1455 for (k
= 0; k
< bset
->n_ineq
; ++k
) {
1456 h
= set_hash_index(index
, size
, bits
, bset
, k
);
1459 l
= index
[h
] - &context
->ineq
[0];
1460 if (isl_int_lt(bset
->ineq
[k
][0], context
->ineq
[l
][0]))
1462 bset
= isl_basic_set_cow(bset
);
1465 isl_basic_set_drop_inequality(bset
, k
);
1475 /* Tighten (decrease) the constant terms of the inequalities based
1476 * on the equalities, without removing any integer points.
1477 * For example, if there is an equality
1485 * then we want to replace the inequality by
1489 * We do this by computing a variable compression and translating
1490 * the constraints to the compressed space.
1491 * If any constraint has coefficients (except the contant term)
1492 * with a common factor "f", then we can replace the constant term "c"
1499 * f * floor(c/f) - c = -fract(c/f)
1501 * and we can add the same value to the original constraint.
1503 * In the example, the compressed space only contains "j",
1504 * and the inequality translates to
1508 * We add -fract(-1/3) = -2 to the original constraint to obtain
1512 static struct isl_basic_set
*normalize_constraints_in_compressed_space(
1513 struct isl_basic_set
*bset
)
1517 struct isl_mat
*B
, *C
;
1523 if (ISL_F_ISSET(bset
, ISL_BASIC_SET_RATIONAL
))
1529 bset
= isl_basic_set_cow(bset
);
1533 total
= isl_basic_set_total_dim(bset
);
1534 B
= isl_mat_sub_alloc(bset
->ctx
, bset
->eq
, 0, bset
->n_eq
, 0, 1 + total
);
1535 C
= isl_mat_variable_compression(B
, NULL
);
1538 if (C
->n_col
== 0) {
1540 return isl_basic_set_set_to_empty(bset
);
1542 B
= isl_mat_sub_alloc(bset
->ctx
, bset
->ineq
,
1543 0, bset
->n_ineq
, 0, 1 + total
);
1544 C
= isl_mat_product(B
, C
);
1549 for (i
= 0; i
< bset
->n_ineq
; ++i
) {
1550 isl_seq_gcd(C
->row
[i
] + 1, C
->n_col
- 1, &gcd
);
1551 if (isl_int_is_one(gcd
))
1553 isl_int_fdiv_r(C
->row
[i
][0], C
->row
[i
][0], gcd
);
1554 isl_int_sub(bset
->ineq
[i
][0], bset
->ineq
[i
][0], C
->row
[i
][0]);
1563 /* Remove all information from bset that is redundant in the context
1564 * of context. Both bset and context are assumed to be full-dimensional.
1566 * We first * remove the inequalities from "bset"
1567 * that are obviously redundant with respect to some inequality in "context".
1569 * If there are any inequalities left, we construct a tableau for
1570 * the context and then add the inequalities of "bset".
1571 * Before adding these inequalities, we freeze all constraints such that
1572 * they won't be considered redundant in terms of the constraints of "bset".
1573 * Then we detect all redundant constraints (among the
1574 * constraints that weren't frozen), first by checking for redundancy in the
1575 * the tableau and then by checking if replacing a constraint by its negation
1576 * would lead to an empty set. This last step is fairly expensive
1577 * and could be optimized by more reuse of the tableau.
1578 * Finally, we update bset according to the results.
1580 static __isl_give isl_basic_set
*uset_gist_full(__isl_take isl_basic_set
*bset
,
1581 __isl_take isl_basic_set
*context
)
1584 isl_basic_set
*combined
= NULL
;
1585 struct isl_tab
*tab
= NULL
;
1586 unsigned context_ineq
;
1589 if (!bset
|| !context
)
1592 if (isl_basic_set_is_universe(bset
)) {
1593 isl_basic_set_free(context
);
1597 if (isl_basic_set_is_universe(context
)) {
1598 isl_basic_set_free(context
);
1602 bset
= remove_shifted_constraints(bset
, context
);
1605 if (bset
->n_ineq
== 0)
1608 context_ineq
= context
->n_ineq
;
1609 combined
= isl_basic_set_cow(isl_basic_set_copy(context
));
1610 combined
= isl_basic_set_extend_constraints(combined
, 0, bset
->n_ineq
);
1611 tab
= isl_tab_from_basic_set(combined
);
1612 for (i
= 0; i
< context_ineq
; ++i
)
1613 if (isl_tab_freeze_constraint(tab
, i
) < 0)
1615 tab
= isl_tab_extend(tab
, bset
->n_ineq
);
1616 for (i
= 0; i
< bset
->n_ineq
; ++i
)
1617 if (isl_tab_add_ineq(tab
, bset
->ineq
[i
]) < 0)
1619 bset
= isl_basic_set_add_constraints(combined
, bset
, 0);
1623 if (isl_tab_detect_redundant(tab
) < 0)
1625 total
= isl_basic_set_total_dim(bset
);
1626 for (i
= context_ineq
; i
< bset
->n_ineq
; ++i
) {
1628 if (tab
->con
[i
].is_redundant
)
1630 tab
->con
[i
].is_redundant
= 1;
1631 combined
= isl_basic_set_dup(bset
);
1632 combined
= isl_basic_set_update_from_tab(combined
, tab
);
1633 combined
= isl_basic_set_extend_constraints(combined
, 0, 1);
1634 k
= isl_basic_set_alloc_inequality(combined
);
1637 isl_seq_neg(combined
->ineq
[k
], bset
->ineq
[i
], 1 + total
);
1638 isl_int_sub_ui(combined
->ineq
[k
][0], combined
->ineq
[k
][0], 1);
1639 is_empty
= isl_basic_set_is_empty(combined
);
1642 isl_basic_set_free(combined
);
1645 tab
->con
[i
].is_redundant
= 0;
1647 for (i
= 0; i
< context_ineq
; ++i
)
1648 tab
->con
[i
].is_redundant
= 1;
1649 bset
= isl_basic_set_update_from_tab(bset
, tab
);
1651 ISL_F_SET(bset
, ISL_BASIC_SET_NO_IMPLICIT
);
1652 ISL_F_SET(bset
, ISL_BASIC_SET_NO_REDUNDANT
);
1657 bset
= isl_basic_set_simplify(bset
);
1658 bset
= isl_basic_set_finalize(bset
);
1659 isl_basic_set_free(context
);
1663 isl_basic_set_free(combined
);
1664 isl_basic_set_free(context
);
1665 isl_basic_set_free(bset
);
1669 /* Remove all information from bset that is redundant in the context
1670 * of context. In particular, equalities that are linear combinations
1671 * of those in context are removed. Then the inequalities that are
1672 * redundant in the context of the equalities and inequalities of
1673 * context are removed.
1675 * We first compute the integer affine hull of the intersection,
1676 * compute the gist inside this affine hull and then add back
1677 * those equalities that are not implied by the context.
1679 static __isl_give isl_basic_set
*uset_gist(__isl_take isl_basic_set
*bset
,
1680 __isl_take isl_basic_set
*context
)
1685 isl_basic_set
*aff_context
;
1688 if (!bset
|| !context
)
1691 bset
= isl_basic_set_intersect(bset
, isl_basic_set_copy(context
));
1692 if (isl_basic_set_fast_is_empty(bset
)) {
1693 isl_basic_set_free(context
);
1696 aff
= isl_basic_set_affine_hull(isl_basic_set_copy(bset
));
1699 if (isl_basic_set_fast_is_empty(aff
)) {
1700 isl_basic_set_free(aff
);
1701 isl_basic_set_free(context
);
1704 if (aff
->n_eq
== 0) {
1705 isl_basic_set_free(aff
);
1706 return uset_gist_full(bset
, context
);
1708 total
= isl_basic_set_total_dim(bset
);
1709 eq
= isl_mat_sub_alloc(bset
->ctx
, aff
->eq
, 0, aff
->n_eq
, 0, 1 + total
);
1710 eq
= isl_mat_cow(eq
);
1711 T
= isl_mat_variable_compression(eq
, &T2
);
1712 if (T
&& T
->n_col
== 0) {
1715 isl_basic_set_free(context
);
1716 isl_basic_set_free(aff
);
1717 return isl_basic_set_set_to_empty(bset
);
1720 aff_context
= isl_basic_set_affine_hull(isl_basic_set_copy(context
));
1722 bset
= isl_basic_set_preimage(bset
, isl_mat_copy(T
));
1723 context
= isl_basic_set_preimage(context
, T
);
1725 bset
= uset_gist_full(bset
, context
);
1726 bset
= isl_basic_set_preimage(bset
, T2
);
1727 bset
= isl_basic_set_intersect(bset
, aff
);
1728 bset
= isl_basic_set_reduce_using_equalities(bset
, aff_context
);
1731 ISL_F_SET(bset
, ISL_BASIC_SET_NO_IMPLICIT
);
1732 ISL_F_SET(bset
, ISL_BASIC_SET_NO_REDUNDANT
);
1737 isl_basic_set_free(bset
);
1738 isl_basic_set_free(context
);
1742 /* Normalize the divs in "bmap" in the context of the equalities in "context".
1743 * We simply add the equalities in context to bmap and then do a regular
1744 * div normalizations. Better results can be obtained by normalizing
1745 * only the divs in bmap than do not also appear in context.
1746 * We need to be careful to reduce the divs using the equalities
1747 * so that later calls to isl_basic_map_overlying_set wouldn't introduce
1748 * spurious constraints.
1750 static struct isl_basic_map
*normalize_divs_in_context(
1751 struct isl_basic_map
*bmap
, struct isl_basic_map
*context
)
1754 unsigned total_context
;
1757 div_eq
= n_pure_div_eq(bmap
);
1761 if (context
->n_div
> 0)
1762 bmap
= isl_basic_map_align_divs(bmap
, context
);
1764 total_context
= isl_basic_map_total_dim(context
);
1765 bmap
= isl_basic_map_extend_constraints(bmap
, context
->n_eq
, 0);
1766 for (i
= 0; i
< context
->n_eq
; ++i
) {
1768 k
= isl_basic_map_alloc_equality(bmap
);
1769 isl_seq_cpy(bmap
->eq
[k
], context
->eq
[i
], 1 + total_context
);
1770 isl_seq_clr(bmap
->eq
[k
] + 1 + total_context
,
1771 isl_basic_map_total_dim(bmap
) - total_context
);
1773 bmap
= isl_basic_map_gauss(bmap
, NULL
);
1774 bmap
= normalize_divs(bmap
, NULL
);
1775 bmap
= isl_basic_map_gauss(bmap
, NULL
);
1779 struct isl_basic_map
*isl_basic_map_gist(struct isl_basic_map
*bmap
,
1780 struct isl_basic_map
*context
)
1782 struct isl_basic_set
*bset
;
1784 if (!bmap
|| !context
)
1787 if (isl_basic_map_is_universe(context
)) {
1788 isl_basic_map_free(context
);
1791 if (isl_basic_map_is_universe(bmap
)) {
1792 isl_basic_map_free(context
);
1795 if (isl_basic_map_fast_is_empty(context
)) {
1796 struct isl_dim
*dim
= isl_dim_copy(bmap
->dim
);
1797 isl_basic_map_free(context
);
1798 isl_basic_map_free(bmap
);
1799 return isl_basic_map_universe(dim
);
1801 if (isl_basic_map_fast_is_empty(bmap
)) {
1802 isl_basic_map_free(context
);
1806 bmap
= isl_basic_map_convex_hull(bmap
);
1807 context
= isl_basic_map_convex_hull(context
);
1810 bmap
= normalize_divs_in_context(bmap
, context
);
1812 context
= isl_basic_map_align_divs(context
, bmap
);
1813 bmap
= isl_basic_map_align_divs(bmap
, context
);
1815 bset
= uset_gist(isl_basic_map_underlying_set(isl_basic_map_copy(bmap
)),
1816 isl_basic_map_underlying_set(context
));
1818 return isl_basic_map_overlying_set(bset
, bmap
);
1820 isl_basic_map_free(bmap
);
1821 isl_basic_map_free(context
);
1826 * Assumes context has no implicit divs.
1828 __isl_give isl_map
*isl_map_gist_basic_map(__isl_take isl_map
*map
,
1829 __isl_take isl_basic_map
*context
)
1833 if (!map
|| !context
)
1836 if (isl_basic_map_is_universe(context
)) {
1837 isl_basic_map_free(context
);
1840 if (isl_basic_map_fast_is_empty(context
)) {
1841 struct isl_dim
*dim
= isl_dim_copy(map
->dim
);
1842 isl_basic_map_free(context
);
1844 return isl_map_universe(dim
);
1847 context
= isl_basic_map_convex_hull(context
);
1848 map
= isl_map_cow(map
);
1849 if (!map
|| !context
)
1851 isl_assert(map
->ctx
, isl_dim_equal(map
->dim
, context
->dim
), goto error
);
1852 map
= isl_map_compute_divs(map
);
1853 for (i
= 0; i
< map
->n
; ++i
)
1854 context
= isl_basic_map_align_divs(context
, map
->p
[i
]);
1855 for (i
= 0; i
< map
->n
; ++i
) {
1856 map
->p
[i
] = isl_basic_map_gist(map
->p
[i
],
1857 isl_basic_map_copy(context
));
1861 isl_basic_map_free(context
);
1862 ISL_F_CLR(map
, ISL_MAP_NORMALIZED
);
1866 isl_basic_map_free(context
);
1870 __isl_give isl_map
*isl_map_gist(__isl_take isl_map
*map
,
1871 __isl_take isl_map
*context
)
1873 return isl_map_gist_basic_map(map
, isl_map_convex_hull(context
));
1876 struct isl_basic_set
*isl_basic_set_gist(struct isl_basic_set
*bset
,
1877 struct isl_basic_set
*context
)
1879 return (struct isl_basic_set
*)isl_basic_map_gist(
1880 (struct isl_basic_map
*)bset
, (struct isl_basic_map
*)context
);
1883 __isl_give isl_set
*isl_set_gist_basic_set(__isl_take isl_set
*set
,
1884 __isl_take isl_basic_set
*context
)
1886 return (struct isl_set
*)isl_map_gist_basic_map((struct isl_map
*)set
,
1887 (struct isl_basic_map
*)context
);
1890 __isl_give isl_set
*isl_set_gist(__isl_take isl_set
*set
,
1891 __isl_take isl_set
*context
)
1893 return (struct isl_set
*)isl_map_gist((struct isl_map
*)set
,
1894 (struct isl_map
*)context
);
1897 /* Quick check to see if two basic maps are disjoint.
1898 * In particular, we reduce the equalities and inequalities of
1899 * one basic map in the context of the equalities of the other
1900 * basic map and check if we get a contradiction.
1902 int isl_basic_map_fast_is_disjoint(struct isl_basic_map
*bmap1
,
1903 struct isl_basic_map
*bmap2
)
1905 struct isl_vec
*v
= NULL
;
1910 if (!bmap1
|| !bmap2
)
1912 isl_assert(bmap1
->ctx
, isl_dim_equal(bmap1
->dim
, bmap2
->dim
),
1914 if (bmap1
->n_div
|| bmap2
->n_div
)
1916 if (!bmap1
->n_eq
&& !bmap2
->n_eq
)
1919 total
= isl_dim_total(bmap1
->dim
);
1922 v
= isl_vec_alloc(bmap1
->ctx
, 1 + total
);
1925 elim
= isl_alloc_array(bmap1
->ctx
, int, total
);
1928 compute_elimination_index(bmap1
, elim
);
1929 for (i
= 0; i
< bmap2
->n_eq
; ++i
) {
1931 reduced
= reduced_using_equalities(v
->block
.data
, bmap2
->eq
[i
],
1933 if (reduced
&& !isl_int_is_zero(v
->block
.data
[0]) &&
1934 isl_seq_first_non_zero(v
->block
.data
+ 1, total
) == -1)
1937 for (i
= 0; i
< bmap2
->n_ineq
; ++i
) {
1939 reduced
= reduced_using_equalities(v
->block
.data
,
1940 bmap2
->ineq
[i
], bmap1
, elim
);
1941 if (reduced
&& isl_int_is_neg(v
->block
.data
[0]) &&
1942 isl_seq_first_non_zero(v
->block
.data
+ 1, total
) == -1)
1945 compute_elimination_index(bmap2
, elim
);
1946 for (i
= 0; i
< bmap1
->n_ineq
; ++i
) {
1948 reduced
= reduced_using_equalities(v
->block
.data
,
1949 bmap1
->ineq
[i
], bmap2
, elim
);
1950 if (reduced
&& isl_int_is_neg(v
->block
.data
[0]) &&
1951 isl_seq_first_non_zero(v
->block
.data
+ 1, total
) == -1)
1967 int isl_basic_set_fast_is_disjoint(struct isl_basic_set
*bset1
,
1968 struct isl_basic_set
*bset2
)
1970 return isl_basic_map_fast_is_disjoint((struct isl_basic_map
*)bset1
,
1971 (struct isl_basic_map
*)bset2
);
1974 int isl_map_fast_is_disjoint(struct isl_map
*map1
, struct isl_map
*map2
)
1981 if (isl_map_fast_is_equal(map1
, map2
))
1984 for (i
= 0; i
< map1
->n
; ++i
) {
1985 for (j
= 0; j
< map2
->n
; ++j
) {
1986 int d
= isl_basic_map_fast_is_disjoint(map1
->p
[i
],
1995 int isl_set_fast_is_disjoint(struct isl_set
*set1
, struct isl_set
*set2
)
1997 return isl_map_fast_is_disjoint((struct isl_map
*)set1
,
1998 (struct isl_map
*)set2
);
2001 /* Check if we can combine a given div with lower bound l and upper
2002 * bound u with some other div and if so return that other div.
2003 * Otherwise return -1.
2005 * We first check that
2006 * - the bounds are opposites of each other (except for the constant
2008 * - the bounds do not reference any other div
2009 * - no div is defined in terms of this div
2011 * Let m be the size of the range allowed on the div by the bounds.
2012 * That is, the bounds are of the form
2014 * e <= a <= e + m - 1
2016 * with e some expression in the other variables.
2017 * We look for another div b such that no third div is defined in terms
2018 * of this second div b and such that in any constraint that contains
2019 * a (except for the given lower and upper bound), also contains b
2020 * with a coefficient that is m times that of b.
2021 * That is, all constraints (execpt for the lower and upper bound)
2024 * e + f (a + m b) >= 0
2026 * If so, we return b so that "a + m b" can be replaced by
2027 * a single div "c = a + m b".
2029 static int div_find_coalesce(struct isl_basic_map
*bmap
, int *pairs
,
2030 unsigned div
, unsigned l
, unsigned u
)
2036 if (bmap
->n_div
<= 1)
2038 dim
= isl_dim_total(bmap
->dim
);
2039 if (isl_seq_first_non_zero(bmap
->ineq
[l
] + 1 + dim
, div
) != -1)
2041 if (isl_seq_first_non_zero(bmap
->ineq
[l
] + 1 + dim
+ div
+ 1,
2042 bmap
->n_div
- div
- 1) != -1)
2044 if (!isl_seq_is_neg(bmap
->ineq
[l
] + 1, bmap
->ineq
[u
] + 1,
2048 for (i
= 0; i
< bmap
->n_div
; ++i
) {
2049 if (isl_int_is_zero(bmap
->div
[i
][0]))
2051 if (!isl_int_is_zero(bmap
->div
[i
][1 + 1 + dim
+ div
]))
2055 isl_int_add(bmap
->ineq
[l
][0], bmap
->ineq
[l
][0], bmap
->ineq
[u
][0]);
2056 if (isl_int_is_neg(bmap
->ineq
[l
][0])) {
2057 isl_int_sub(bmap
->ineq
[l
][0],
2058 bmap
->ineq
[l
][0], bmap
->ineq
[u
][0]);
2059 bmap
= isl_basic_map_copy(bmap
);
2060 bmap
= isl_basic_map_set_to_empty(bmap
);
2061 isl_basic_map_free(bmap
);
2064 isl_int_add_ui(bmap
->ineq
[l
][0], bmap
->ineq
[l
][0], 1);
2065 for (i
= 0; i
< bmap
->n_div
; ++i
) {
2070 for (j
= 0; j
< bmap
->n_div
; ++j
) {
2071 if (isl_int_is_zero(bmap
->div
[j
][0]))
2073 if (!isl_int_is_zero(bmap
->div
[j
][1 + 1 + dim
+ i
]))
2076 if (j
< bmap
->n_div
)
2078 for (j
= 0; j
< bmap
->n_ineq
; ++j
) {
2080 if (j
== l
|| j
== u
)
2082 if (isl_int_is_zero(bmap
->ineq
[j
][1 + dim
+ div
]))
2084 if (isl_int_is_zero(bmap
->ineq
[j
][1 + dim
+ i
]))
2086 isl_int_mul(bmap
->ineq
[j
][1 + dim
+ div
],
2087 bmap
->ineq
[j
][1 + dim
+ div
],
2089 valid
= isl_int_eq(bmap
->ineq
[j
][1 + dim
+ div
],
2090 bmap
->ineq
[j
][1 + dim
+ i
]);
2091 isl_int_divexact(bmap
->ineq
[j
][1 + dim
+ div
],
2092 bmap
->ineq
[j
][1 + dim
+ div
],
2097 if (j
< bmap
->n_ineq
)
2102 isl_int_sub_ui(bmap
->ineq
[l
][0], bmap
->ineq
[l
][0], 1);
2103 isl_int_sub(bmap
->ineq
[l
][0], bmap
->ineq
[l
][0], bmap
->ineq
[u
][0]);
2107 /* Given a lower and an upper bound on div i, construct an inequality
2108 * that when nonnegative ensures that this pair of bounds always allows
2109 * for an integer value of the given div.
2110 * The lower bound is inequality l, while the upper bound is inequality u.
2111 * The constructed inequality is stored in ineq.
2112 * g, fl, fu are temporary scalars.
2114 * Let the upper bound be
2118 * and the lower bound
2122 * Let n_u = f_u g and n_l = f_l g, with g = gcd(n_u, n_l).
2125 * - f_u e_l <= f_u f_l g a <= f_l e_u
2127 * Since all variables are integer valued, this is equivalent to
2129 * - f_u e_l - (f_u - 1) <= f_u f_l g a <= f_l e_u + (f_l - 1)
2131 * If this interval is at least f_u f_l g, then it contains at least
2132 * one integer value for a.
2133 * That is, the test constraint is
2135 * f_l e_u + f_u e_l + f_l - 1 + f_u - 1 + 1 >= f_u f_l g
2137 static void construct_test_ineq(struct isl_basic_map
*bmap
, int i
,
2138 int l
, int u
, isl_int
*ineq
, isl_int g
, isl_int fl
, isl_int fu
)
2141 dim
= isl_dim_total(bmap
->dim
);
2143 isl_int_gcd(g
, bmap
->ineq
[l
][1 + dim
+ i
], bmap
->ineq
[u
][1 + dim
+ i
]);
2144 isl_int_divexact(fl
, bmap
->ineq
[l
][1 + dim
+ i
], g
);
2145 isl_int_divexact(fu
, bmap
->ineq
[u
][1 + dim
+ i
], g
);
2146 isl_int_neg(fu
, fu
);
2147 isl_seq_combine(ineq
, fl
, bmap
->ineq
[u
], fu
, bmap
->ineq
[l
],
2148 1 + dim
+ bmap
->n_div
);
2149 isl_int_add(ineq
[0], ineq
[0], fl
);
2150 isl_int_add(ineq
[0], ineq
[0], fu
);
2151 isl_int_sub_ui(ineq
[0], ineq
[0], 1);
2152 isl_int_mul(g
, g
, fl
);
2153 isl_int_mul(g
, g
, fu
);
2154 isl_int_sub(ineq
[0], ineq
[0], g
);
2157 /* Remove more kinds of divs that are not strictly needed.
2158 * In particular, if all pairs of lower and upper bounds on a div
2159 * are such that they allow at least one integer value of the div,
2160 * the we can eliminate the div using Fourier-Motzkin without
2161 * introducing any spurious solutions.
2163 static struct isl_basic_map
*drop_more_redundant_divs(
2164 struct isl_basic_map
*bmap
, int *pairs
, int n
)
2166 struct isl_tab
*tab
= NULL
;
2167 struct isl_vec
*vec
= NULL
;
2179 dim
= isl_dim_total(bmap
->dim
);
2180 vec
= isl_vec_alloc(bmap
->ctx
, 1 + dim
+ bmap
->n_div
);
2184 tab
= isl_tab_from_basic_map(bmap
);
2189 enum isl_lp_result res
;
2191 for (i
= 0; i
< bmap
->n_div
; ++i
) {
2194 if (best
>= 0 && pairs
[best
] <= pairs
[i
])
2200 for (l
= 0; l
< bmap
->n_ineq
; ++l
) {
2201 if (!isl_int_is_pos(bmap
->ineq
[l
][1 + dim
+ i
]))
2203 for (u
= 0; u
< bmap
->n_ineq
; ++u
) {
2204 if (!isl_int_is_neg(bmap
->ineq
[u
][1 + dim
+ i
]))
2206 construct_test_ineq(bmap
, i
, l
, u
,
2207 vec
->el
, g
, fl
, fu
);
2208 res
= isl_tab_min(tab
, vec
->el
,
2209 bmap
->ctx
->one
, &g
, NULL
, 0);
2210 if (res
== isl_lp_error
)
2212 if (res
== isl_lp_empty
) {
2213 bmap
= isl_basic_map_set_to_empty(bmap
);
2216 if (res
!= isl_lp_ok
|| isl_int_is_neg(g
))
2219 if (u
< bmap
->n_ineq
)
2222 if (l
== bmap
->n_ineq
) {
2242 bmap
= isl_basic_map_remove(bmap
, isl_dim_div
, remove
, 1);
2243 return isl_basic_map_drop_redundant_divs(bmap
);
2246 isl_basic_map_free(bmap
);
2255 /* Given a pair of divs div1 and div2 such that, expect for the lower bound l
2256 * and the upper bound u, div1 always occurs together with div2 in the form
2257 * (div1 + m div2), where m is the constant range on the variable div1
2258 * allowed by l and u, replace the pair div1 and div2 by a single
2259 * div that is equal to div1 + m div2.
2261 * The new div will appear in the location that contains div2.
2262 * We need to modify all constraints that contain
2263 * div2 = (div - div1) / m
2264 * (If a constraint does not contain div2, it will also not contain div1.)
2265 * If the constraint also contains div1, then we know they appear
2266 * as f (div1 + m div2) and we can simply replace (div1 + m div2) by div,
2267 * i.e., the coefficient of div is f.
2269 * Otherwise, we first need to introduce div1 into the constraint.
2278 * A lower bound on div2
2282 * can be replaced by
2284 * (n * (m div 2 + div1) + m t + n f)/g >= 0
2286 * with g = gcd(m,n).
2291 * can be replaced by
2293 * (-n * (m div2 + div1) + m t + n f')/g >= 0
2295 * These constraint are those that we would obtain from eliminating
2296 * div1 using Fourier-Motzkin.
2298 * After all constraints have been modified, we drop the lower and upper
2299 * bound and then drop div1.
2301 static struct isl_basic_map
*coalesce_divs(struct isl_basic_map
*bmap
,
2302 unsigned div1
, unsigned div2
, unsigned l
, unsigned u
)
2307 unsigned dim
, total
;
2310 dim
= isl_dim_total(bmap
->dim
);
2311 total
= 1 + dim
+ bmap
->n_div
;
2316 isl_int_add(m
, bmap
->ineq
[l
][0], bmap
->ineq
[u
][0]);
2317 isl_int_add_ui(m
, m
, 1);
2319 for (i
= 0; i
< bmap
->n_ineq
; ++i
) {
2320 if (i
== l
|| i
== u
)
2322 if (isl_int_is_zero(bmap
->ineq
[i
][1 + dim
+ div2
]))
2324 if (isl_int_is_zero(bmap
->ineq
[i
][1 + dim
+ div1
])) {
2325 isl_int_gcd(b
, m
, bmap
->ineq
[i
][1 + dim
+ div2
]);
2326 isl_int_divexact(a
, m
, b
);
2327 isl_int_divexact(b
, bmap
->ineq
[i
][1 + dim
+ div2
], b
);
2328 if (isl_int_is_pos(b
)) {
2329 isl_seq_combine(bmap
->ineq
[i
], a
, bmap
->ineq
[i
],
2330 b
, bmap
->ineq
[l
], total
);
2333 isl_seq_combine(bmap
->ineq
[i
], a
, bmap
->ineq
[i
],
2334 b
, bmap
->ineq
[u
], total
);
2337 isl_int_set(bmap
->ineq
[i
][1 + dim
+ div2
],
2338 bmap
->ineq
[i
][1 + dim
+ div1
]);
2339 isl_int_set_si(bmap
->ineq
[i
][1 + dim
+ div1
], 0);
2346 isl_basic_map_drop_inequality(bmap
, l
);
2347 isl_basic_map_drop_inequality(bmap
, u
);
2349 isl_basic_map_drop_inequality(bmap
, u
);
2350 isl_basic_map_drop_inequality(bmap
, l
);
2352 bmap
= isl_basic_map_drop_div(bmap
, div1
);
2356 /* First check if we can coalesce any pair of divs and
2357 * then continue with dropping more redundant divs.
2359 * We loop over all pairs of lower and upper bounds on a div
2360 * with coefficient 1 and -1, respectively, check if there
2361 * is any other div "c" with which we can coalesce the div
2362 * and if so, perform the coalescing.
2364 static struct isl_basic_map
*coalesce_or_drop_more_redundant_divs(
2365 struct isl_basic_map
*bmap
, int *pairs
, int n
)
2370 dim
= isl_dim_total(bmap
->dim
);
2372 for (i
= 0; i
< bmap
->n_div
; ++i
) {
2375 for (l
= 0; l
< bmap
->n_ineq
; ++l
) {
2376 if (!isl_int_is_one(bmap
->ineq
[l
][1 + dim
+ i
]))
2378 for (u
= 0; u
< bmap
->n_ineq
; ++u
) {
2381 if (!isl_int_is_negone(bmap
->ineq
[u
][1+dim
+i
]))
2383 c
= div_find_coalesce(bmap
, pairs
, i
, l
, u
);
2387 bmap
= coalesce_divs(bmap
, i
, c
, l
, u
);
2388 return isl_basic_map_drop_redundant_divs(bmap
);
2393 if (ISL_F_ISSET(bmap
, ISL_BASIC_MAP_EMPTY
))
2396 return drop_more_redundant_divs(bmap
, pairs
, n
);
2399 /* Remove divs that are not strictly needed.
2400 * In particular, if a div only occurs positively (or negatively)
2401 * in constraints, then it can simply be dropped.
2402 * Also, if a div occurs only occurs in two constraints and if moreover
2403 * those two constraints are opposite to each other, except for the constant
2404 * term and if the sum of the constant terms is such that for any value
2405 * of the other values, there is always at least one integer value of the
2406 * div, i.e., if one plus this sum is greater than or equal to
2407 * the (absolute value) of the coefficent of the div in the constraints,
2408 * then we can also simply drop the div.
2410 * If any divs are left after these simple checks then we move on
2411 * to more complicated cases in drop_more_redundant_divs.
2413 struct isl_basic_map
*isl_basic_map_drop_redundant_divs(
2414 struct isl_basic_map
*bmap
)
2424 off
= isl_dim_total(bmap
->dim
);
2425 pairs
= isl_calloc_array(bmap
->ctx
, int, bmap
->n_div
);
2429 for (i
= 0; i
< bmap
->n_div
; ++i
) {
2431 int last_pos
, last_neg
;
2435 defined
= !isl_int_is_zero(bmap
->div
[i
][0]);
2436 for (j
= 0; j
< bmap
->n_eq
; ++j
)
2437 if (!isl_int_is_zero(bmap
->eq
[j
][1 + off
+ i
]))
2443 for (j
= 0; j
< bmap
->n_ineq
; ++j
) {
2444 if (isl_int_is_pos(bmap
->ineq
[j
][1 + off
+ i
])) {
2448 if (isl_int_is_neg(bmap
->ineq
[j
][1 + off
+ i
])) {
2453 pairs
[i
] = pos
* neg
;
2454 if (pairs
[i
] == 0) {
2455 for (j
= bmap
->n_ineq
- 1; j
>= 0; --j
)
2456 if (!isl_int_is_zero(bmap
->ineq
[j
][1+off
+i
]))
2457 isl_basic_map_drop_inequality(bmap
, j
);
2458 bmap
= isl_basic_map_drop_div(bmap
, i
);
2460 return isl_basic_map_drop_redundant_divs(bmap
);
2464 if (!isl_seq_is_neg(bmap
->ineq
[last_pos
] + 1,
2465 bmap
->ineq
[last_neg
] + 1,
2469 isl_int_add(bmap
->ineq
[last_pos
][0],
2470 bmap
->ineq
[last_pos
][0], bmap
->ineq
[last_neg
][0]);
2471 isl_int_add_ui(bmap
->ineq
[last_pos
][0],
2472 bmap
->ineq
[last_pos
][0], 1);
2473 redundant
= isl_int_ge(bmap
->ineq
[last_pos
][0],
2474 bmap
->ineq
[last_pos
][1+off
+i
]);
2475 isl_int_sub_ui(bmap
->ineq
[last_pos
][0],
2476 bmap
->ineq
[last_pos
][0], 1);
2477 isl_int_sub(bmap
->ineq
[last_pos
][0],
2478 bmap
->ineq
[last_pos
][0], bmap
->ineq
[last_neg
][0]);
2481 !ok_to_set_div_from_bound(bmap
, i
, last_pos
)) {
2486 bmap
= set_div_from_lower_bound(bmap
, i
, last_pos
);
2487 bmap
= isl_basic_map_simplify(bmap
);
2489 return isl_basic_map_drop_redundant_divs(bmap
);
2491 if (last_pos
> last_neg
) {
2492 isl_basic_map_drop_inequality(bmap
, last_pos
);
2493 isl_basic_map_drop_inequality(bmap
, last_neg
);
2495 isl_basic_map_drop_inequality(bmap
, last_neg
);
2496 isl_basic_map_drop_inequality(bmap
, last_pos
);
2498 bmap
= isl_basic_map_drop_div(bmap
, i
);
2500 return isl_basic_map_drop_redundant_divs(bmap
);
2504 return coalesce_or_drop_more_redundant_divs(bmap
, pairs
, n
);
2510 isl_basic_map_free(bmap
);
2514 struct isl_basic_set
*isl_basic_set_drop_redundant_divs(
2515 struct isl_basic_set
*bset
)
2517 return (struct isl_basic_set
*)
2518 isl_basic_map_drop_redundant_divs((struct isl_basic_map
*)bset
);
2521 struct isl_map
*isl_map_drop_redundant_divs(struct isl_map
*map
)
2527 for (i
= 0; i
< map
->n
; ++i
) {
2528 map
->p
[i
] = isl_basic_map_drop_redundant_divs(map
->p
[i
]);
2532 ISL_F_CLR(map
, ISL_MAP_NORMALIZED
);
2539 struct isl_set
*isl_set_drop_redundant_divs(struct isl_set
*set
)
2541 return (struct isl_set
*)
2542 isl_map_drop_redundant_divs((struct isl_map
*)set
);