+/*
+ * Copyright 2008-2009 Katholieke Universiteit Leuven
+ *
+ * Use of this software is governed by the GNU LGPLv2.1 license
+ *
+ * Written by Sven Verdoolaege, K.U.Leuven, Departement
+ * Computerwetenschappen, Celestijnenlaan 200A, B-3001 Leuven, Belgium
+ */
+
#include "isl_equalities.h"
#include "isl_map.h"
#include "isl_map_private.h"
+#include "isl_seq.h"
#include "isl_tab.h"
static void swap_equality(struct isl_basic_map *bmap, int a, int b)
return NULL;
}
-/* Drop n input dimensions starting at first.
+/* Move "n" divs starting at "first" to the end of the list of divs.
+ */
+static struct isl_basic_map *move_divs_last(struct isl_basic_map *bmap,
+ unsigned first, unsigned n)
+{
+ isl_int **div;
+ int i;
+
+ if (first + n == bmap->n_div)
+ return bmap;
+
+ div = isl_alloc_array(bmap->ctx, isl_int *, n);
+ if (!div)
+ goto error;
+ for (i = 0; i < n; ++i)
+ div[i] = bmap->div[first + i];
+ for (i = 0; i < bmap->n_div - first - n; ++i)
+ bmap->div[first + i] = bmap->div[first + n + i];
+ for (i = 0; i < n; ++i)
+ bmap->div[bmap->n_div - n + i] = div[i];
+ free(div);
+ return bmap;
+error:
+ isl_basic_map_free(bmap);
+ return NULL;
+}
+
+/* Drop "n" dimensions of type "type" starting at "first".
*
* In principle, this frees up some extra variables as the number
* of columns remains constant, but we would have to extend
for (i = 0; i < bmap->n_div; ++i)
constraint_drop_vars(bmap->div[i]+1+offset, n, left);
- bmap->dim = isl_dim_drop(bmap->dim, type, first, n);
+ if (type == isl_dim_div) {
+ bmap = move_divs_last(bmap, first, n);
+ if (!bmap)
+ goto error;
+ isl_basic_map_free_div(bmap, n);
+ } else
+ bmap->dim = isl_dim_drop(bmap->dim, type, first, n);
if (!bmap->dim)
goto error;
return NULL;
}
+__isl_give isl_basic_set *isl_basic_set_drop(__isl_take isl_basic_set *bset,
+ enum isl_dim_type type, unsigned first, unsigned n)
+{
+ return (isl_basic_set *)isl_basic_map_drop((isl_basic_map *)bset,
+ type, first, n);
+}
+
struct isl_basic_map *isl_basic_map_drop_inputs(
struct isl_basic_map *bmap, unsigned first, unsigned n)
{
return NULL;
}
+struct isl_set *isl_set_drop(struct isl_set *set,
+ enum isl_dim_type type, unsigned first, unsigned n)
+{
+ return (isl_set *)isl_map_drop((isl_map *)set, type, first, n);
+}
+
struct isl_map *isl_map_drop_inputs(
struct isl_map *map, unsigned first, unsigned n)
{
isl_int gcd;
unsigned total = isl_basic_map_total_dim(bmap);
+ if (!bmap)
+ return NULL;
+
isl_int_init(gcd);
for (i = bmap->n_eq - 1; i >= 0; --i) {
isl_seq_gcd(bmap->eq[i]+1, total, &gcd);
struct isl_basic_set *isl_basic_set_normalize_constraints(
struct isl_basic_set *bset)
{
- (struct isl_basic_set *)isl_basic_map_normalize_constraints(
+ return (struct isl_basic_set *)isl_basic_map_normalize_constraints(
(struct isl_basic_map *)bset);
}
-static void eliminate_div(struct isl_basic_map *bmap, isl_int *eq, unsigned div)
+/* Assumes divs have been ordered if keep_divs is set.
+ */
+static void eliminate_var_using_equality(struct isl_basic_map *bmap,
+ unsigned pos, isl_int *eq, int keep_divs, int *progress)
{
- int i;
- unsigned pos = 1 + isl_dim_total(bmap->dim) + div;
- unsigned len;
- len = 1 + isl_basic_map_total_dim(bmap);
+ unsigned total;
+ int k;
+ int last_div;
- for (i = 0; i < bmap->n_eq; ++i)
- if (bmap->eq[i] != eq)
- isl_seq_elim(bmap->eq[i], eq, pos, len, NULL);
+ total = isl_basic_map_total_dim(bmap);
+ last_div = isl_seq_last_non_zero(eq + 1 + isl_dim_total(bmap->dim),
+ bmap->n_div);
+ for (k = 0; k < bmap->n_eq; ++k) {
+ if (bmap->eq[k] == eq)
+ continue;
+ if (isl_int_is_zero(bmap->eq[k][1+pos]))
+ continue;
+ if (progress)
+ *progress = 1;
+ isl_seq_elim(bmap->eq[k], eq, 1+pos, 1+total, NULL);
+ }
- for (i = 0; i < bmap->n_ineq; ++i)
- isl_seq_elim(bmap->ineq[i], eq, pos, len, NULL);
+ for (k = 0; k < bmap->n_ineq; ++k) {
+ if (isl_int_is_zero(bmap->ineq[k][1+pos]))
+ continue;
+ if (progress)
+ *progress = 1;
+ isl_seq_elim(bmap->ineq[k], eq, 1+pos, 1+total, NULL);
+ ISL_F_CLR(bmap, ISL_BASIC_MAP_NORMALIZED);
+ }
- /* We need to be careful about circular definitions,
- * so for now we just remove the definitions of other divs that
- * depend on this div and (possibly) recompute them later.
- */
- for (i = 0; i < bmap->n_div; ++i)
- if (!isl_int_is_zero(bmap->div[i][0]) &&
- !isl_int_is_zero(bmap->div[i][1 + pos]))
- isl_seq_clr(bmap->div[i], 1 + len);
+ for (k = 0; k < bmap->n_div; ++k) {
+ if (isl_int_is_zero(bmap->div[k][0]))
+ continue;
+ if (isl_int_is_zero(bmap->div[k][1+1+pos]))
+ continue;
+ if (progress)
+ *progress = 1;
+ /* We need to be careful about circular definitions,
+ * so for now we just remove the definition of div k
+ * if the equality contains any divs.
+ * If keep_divs is set, then the divs have been ordered
+ * and we can keep the definition as long as the result
+ * is still ordered.
+ */
+ if (last_div == -1 || (keep_divs && last_div < k))
+ isl_seq_elim(bmap->div[k]+1, eq,
+ 1+pos, 1+total, &bmap->div[k][0]);
+ else
+ isl_seq_clr(bmap->div[k], 1 + total);
+ ISL_F_CLR(bmap, ISL_BASIC_MAP_NORMALIZED);
+ }
+}
+
+/* Assumes divs have been ordered if keep_divs is set.
+ */
+static void eliminate_div(struct isl_basic_map *bmap, isl_int *eq,
+ unsigned div, int keep_divs)
+{
+ unsigned pos = isl_dim_total(bmap->dim) + div;
+
+ eliminate_var_using_equality(bmap, pos, eq, keep_divs, NULL);
isl_basic_map_drop_div(bmap, div);
}
+/* Check if elimination of div "div" using equality "eq" would not
+ * result in a div depending on a later div.
+ */
+static int ok_to_eliminate_div(struct isl_basic_map *bmap, isl_int *eq,
+ unsigned div)
+{
+ int k;
+ int last_div;
+ unsigned pos = isl_dim_total(bmap->dim) + div;
+
+ last_div = isl_seq_last_non_zero(eq + 1 + isl_dim_total(bmap->dim),
+ bmap->n_div);
+ if (last_div < 0 || last_div <= div)
+ return 1;
+
+ for (k = 0; k <= last_div; ++k) {
+ if (isl_int_is_zero(bmap->div[k][0]))
+ return 1;
+ if (!isl_int_is_zero(bmap->div[k][1 + 1 + pos]))
+ return 0;
+ }
+
+ return 1;
+}
+
/* Elimininate divs based on equalities
*/
static struct isl_basic_map *eliminate_divs_eq(
int modified = 0;
unsigned off;
+ bmap = isl_basic_map_order_divs(bmap);
+
if (!bmap)
return NULL;
if (!isl_int_is_one(bmap->eq[i][off + d]) &&
!isl_int_is_negone(bmap->eq[i][off + d]))
continue;
+ if (!ok_to_eliminate_div(bmap, bmap->eq[i], d))
+ continue;
modified = 1;
*progress = 1;
- eliminate_div(bmap, bmap->eq[i], d);
+ eliminate_div(bmap, bmap->eq[i], d, 1);
isl_basic_map_drop_equality(bmap, i);
break;
}
continue;
*progress = 1;
bmap = isl_basic_map_eliminate_vars(bmap, (off-1)+d, 1);
- if (ISL_F_ISSET(bmap, ISL_BASIC_MAP_EMPTY))
+ if (!bmap || ISL_F_ISSET(bmap, ISL_BASIC_MAP_EMPTY))
break;
bmap = isl_basic_map_drop_div(bmap, d);
if (!bmap)
return bmap;
}
-static void eliminate_var_using_equality(struct isl_basic_map *bmap,
- unsigned pos, isl_int *eq, int *progress)
-{
- unsigned total;
- int k;
- int contains_divs;
-
- total = isl_basic_map_total_dim(bmap);
- contains_divs =
- isl_seq_first_non_zero(eq + 1 + isl_dim_total(bmap->dim),
- bmap->n_div) != -1;
- for (k = 0; k < bmap->n_eq; ++k) {
- if (bmap->eq[k] == eq)
- continue;
- if (isl_int_is_zero(bmap->eq[k][1+pos]))
- continue;
- if (progress)
- *progress = 1;
- isl_seq_elim(bmap->eq[k], eq, 1+pos, 1+total, NULL);
- }
-
- for (k = 0; k < bmap->n_ineq; ++k) {
- if (isl_int_is_zero(bmap->ineq[k][1+pos]))
- continue;
- if (progress)
- *progress = 1;
- isl_seq_elim(bmap->ineq[k], eq, 1+pos, 1+total, NULL);
- ISL_F_CLR(bmap, ISL_BASIC_MAP_NORMALIZED);
- }
-
- for (k = 0; k < bmap->n_div; ++k) {
- if (isl_int_is_zero(bmap->div[k][0]))
- continue;
- if (isl_int_is_zero(bmap->div[k][1+1+pos]))
- continue;
- if (progress)
- *progress = 1;
- /* We need to be careful about circular definitions,
- * so for now we just remove the definition of div k
- * if the equality contains any divs.
- */
- if (contains_divs)
- isl_seq_clr(bmap->div[k], 1 + total);
- else
- isl_seq_elim(bmap->div[k]+1, eq,
- 1+pos, 1+total, &bmap->div[k][0]);
- ISL_F_CLR(bmap, ISL_BASIC_MAP_NORMALIZED);
- }
-}
-
struct isl_basic_map *isl_basic_map_gauss(
struct isl_basic_map *bmap, int *progress)
{
unsigned total_var;
unsigned total;
+ bmap = isl_basic_map_order_divs(bmap);
+
if (!bmap)
return NULL;
if (isl_int_is_neg(bmap->eq[done][1+last_var]))
isl_seq_neg(bmap->eq[done], bmap->eq[done], 1+total);
- eliminate_var_using_equality(bmap, last_var, bmap->eq[done],
+ eliminate_var_using_equality(bmap, last_var, bmap->eq[done], 1,
progress);
if (last_var >= total_var &&
int k, l, h;
int bits;
struct isl_blk eq;
- unsigned total_var = isl_dim_total(bmap->dim);
- unsigned total = total_var + bmap->n_div;
+ unsigned total_var;
+ unsigned total;
struct isl_ctx *ctx;
- if (bmap->n_div <= 1)
+ if (!bmap || bmap->n_div <= 1)
return bmap;
+ total_var = isl_dim_total(bmap->dim);
+ total = total_var + bmap->n_div;
+
ctx = bmap->ctx;
for (k = bmap->n_div - 1; k >= 0; --k)
if (!isl_int_is_zero(bmap->div[k][0]))
k = elim_for[l] - 1;
isl_int_set_si(eq.data[1+total_var+k], -1);
isl_int_set_si(eq.data[1+total_var+l], 1);
- eliminate_div(bmap, eq.data, l);
+ eliminate_div(bmap, eq.data, l, 0);
isl_int_set_si(eq.data[1+total_var+k], 0);
isl_int_set_si(eq.data[1+total_var+l], 0);
}
if (div_eq < bmap->n_eq) {
B = isl_mat_sub_alloc(bmap->ctx, bmap->eq, div_eq,
bmap->n_eq - div_eq, 0, 1 + total);
- C = isl_mat_variable_compression(bmap->ctx, B, &C2);
+ C = isl_mat_variable_compression(B, &C2);
if (!C || !C2)
goto error;
if (C->n_col == 0) {
bmap = isl_basic_map_set_to_empty(bmap);
- isl_mat_free(bmap->ctx, C);
- isl_mat_free(bmap->ctx, C2);
+ isl_mat_free(C);
+ isl_mat_free(C2);
goto done;
}
}
B = isl_mat_sub_alloc(bmap->ctx, bmap->eq, 0, div_eq, 0, 1 + total);
if (C) {
- B = isl_mat_product(bmap->ctx, B, C);
+ B = isl_mat_product(B, C);
C = NULL;
}
- T = isl_mat_parameter_compression(bmap->ctx, B, d);
+ T = isl_mat_parameter_compression(B, d);
if (!T)
goto error;
if (T->n_col == 0) {
bmap = isl_basic_map_set_to_empty(bmap);
- isl_mat_free(bmap->ctx, C2);
- isl_mat_free(bmap->ctx, T);
+ isl_mat_free(C2);
+ isl_mat_free(T);
goto done;
}
isl_int_init(v);
}
isl_int_clear(v);
pos = isl_alloc_array(bmap->ctx, int, T->n_row);
+ if (!pos)
+ goto error;
/* We have to be careful because dropping equalities may reorder them */
dropped = 0;
for (j = bmap->n_div - 1; j >= 0; --j) {
isl_int_set(bmap->eq[j][pos[i]], bmap->div[k][0]);
}
free(pos);
- isl_mat_free(bmap->ctx, C2);
- isl_mat_free(bmap->ctx, T);
+ isl_mat_free(C2);
+ isl_mat_free(T);
if (progress)
*progress = 1;
return bmap;
error:
- isl_mat_free(bmap->ctx, C);
- isl_mat_free(bmap->ctx, C2);
- isl_mat_free(bmap->ctx, T);
+ isl_mat_free(C);
+ isl_mat_free(C2);
+ isl_mat_free(T);
+ return bmap;
+}
+
+static struct isl_basic_map *set_div_from_lower_bound(
+ struct isl_basic_map *bmap, int div, int ineq)
+{
+ unsigned total = 1 + isl_dim_total(bmap->dim);
+
+ isl_seq_neg(bmap->div[div] + 1, bmap->ineq[ineq], total + bmap->n_div);
+ isl_int_set(bmap->div[div][0], bmap->ineq[ineq][total + div]);
+ isl_int_add(bmap->div[div][1], bmap->div[div][1], bmap->div[div][0]);
+ isl_int_sub_ui(bmap->div[div][1], bmap->div[div][1], 1);
+ isl_int_set_si(bmap->div[div][1 + total + div], 0);
+
+ return bmap;
+}
+
+/* Check whether it is ok to define a div based on an inequality.
+ * To avoid the introduction of circular definitions of divs, we
+ * do not allow such a definition if the resulting expression would refer to
+ * any other undefined divs or if any known div is defined in
+ * terms of the unknown div.
+ */
+static int ok_to_set_div_from_bound(struct isl_basic_map *bmap,
+ int div, int ineq)
+{
+ int j;
+ unsigned total = 1 + isl_dim_total(bmap->dim);
+
+ /* Not defined in terms of unknown divs */
+ for (j = 0; j < bmap->n_div; ++j) {
+ if (div == j)
+ continue;
+ if (isl_int_is_zero(bmap->ineq[ineq][total + j]))
+ continue;
+ if (isl_int_is_zero(bmap->div[j][0]))
+ return 0;
+ }
+
+ /* No other div defined in terms of this one => avoid loops */
+ for (j = 0; j < bmap->n_div; ++j) {
+ if (div == j)
+ continue;
+ if (isl_int_is_zero(bmap->div[j][0]))
+ continue;
+ if (!isl_int_is_zero(bmap->div[j][1 + total + div]))
+ return 0;
+ }
+
+ return 1;
+}
+
+/* Given two constraints "k" and "l" that are opposite to each other,
+ * except for the constant term, check if we can use them
+ * to obtain an expression for one of the hitherto unknown divs.
+ * "sum" is the sum of the constant terms of the constraints.
+ * If this sum is strictly smaller than the coefficient of one
+ * of the divs, then this pair can be used define the div.
+ * To avoid the introduction of circular definitions of divs, we
+ * do not use the pair if the resulting expression would refer to
+ * any other undefined divs or if any known div is defined in
+ * terms of the unknown div.
+ */
+static struct isl_basic_map *check_for_div_constraints(
+ struct isl_basic_map *bmap, int k, int l, isl_int sum, int *progress)
+{
+ int i;
+ unsigned total = 1 + isl_dim_total(bmap->dim);
+
+ for (i = 0; i < bmap->n_div; ++i) {
+ if (!isl_int_is_zero(bmap->div[i][0]))
+ continue;
+ if (isl_int_is_zero(bmap->ineq[k][total + i]))
+ continue;
+ if (isl_int_abs_ge(sum, bmap->ineq[k][total + i]))
+ continue;
+ if (!ok_to_set_div_from_bound(bmap, i, k))
+ break;
+ if (isl_int_is_pos(bmap->ineq[k][total + i]))
+ bmap = set_div_from_lower_bound(bmap, i, k);
+ else
+ bmap = set_div_from_lower_bound(bmap, i, l);
+ if (progress)
+ *progress = 1;
+ break;
+ }
return bmap;
}
unsigned total = isl_basic_map_total_dim(bmap);
isl_int sum;
- if (bmap->n_ineq <= 1)
+ if (!bmap || bmap->n_ineq <= 1)
return bmap;
size = round_up(4 * (bmap->n_ineq+1) / 3 - 1);
continue;
l = index[h] - &bmap->ineq[0];
isl_int_add(sum, bmap->ineq[k][0], bmap->ineq[l][0]);
- if (isl_int_is_pos(sum))
+ if (isl_int_is_pos(sum)) {
+ bmap = check_for_div_constraints(bmap, k, l, sum,
+ progress);
continue;
+ }
if (isl_int_is_zero(sum)) {
/* We need to break out of the loop after these
* changes since the contents of the hash
* will no longer be valid.
* Plus, we probably we want to regauss first.
*/
+ if (progress)
+ *progress = 1;
isl_basic_map_drop_inequality(bmap, l);
isl_basic_map_inequality_to_equality(bmap, k);
} else
}
+int isl_basic_map_is_div_constraint(__isl_keep isl_basic_map *bmap,
+ isl_int *constraint, unsigned div)
+{
+ unsigned pos;
+
+ if (!bmap)
+ return -1;
+
+ pos = 1 + isl_dim_total(bmap->dim) + div;
+
+ if (isl_int_eq(constraint[pos], bmap->div[div][0])) {
+ int neg;
+ isl_int_sub(bmap->div[div][1],
+ bmap->div[div][1], bmap->div[div][0]);
+ isl_int_add_ui(bmap->div[div][1], bmap->div[div][1], 1);
+ neg = isl_seq_is_neg(constraint, bmap->div[div]+1, pos);
+ isl_int_sub_ui(bmap->div[div][1], bmap->div[div][1], 1);
+ isl_int_add(bmap->div[div][1],
+ bmap->div[div][1], bmap->div[div][0]);
+ if (!neg)
+ return 0;
+ if (isl_seq_first_non_zero(constraint+pos+1,
+ bmap->n_div-div-1) != -1)
+ return 0;
+ } else if (isl_int_abs_eq(constraint[pos], bmap->div[div][0])) {
+ if (!isl_seq_eq(constraint, bmap->div[div]+1, pos))
+ return 0;
+ if (isl_seq_first_non_zero(constraint+pos+1,
+ bmap->n_div-div-1) != -1)
+ return 0;
+ } else
+ return 0;
+
+ return 1;
+}
+
+
/* If the only constraints a div d=floor(f/m)
* appears in are its two defining constraints
*
for (i = 0; i < bmap->n_ineq; ++i) {
if (isl_int_is_zero(bmap->ineq[i][pos]))
continue;
- if (isl_int_eq(bmap->ineq[i][pos], bmap->div[div][0])) {
- int neg;
- isl_int_sub(bmap->div[div][1],
- bmap->div[div][1], bmap->div[div][0]);
- isl_int_add_ui(bmap->div[div][1], bmap->div[div][1], 1);
- neg = isl_seq_is_neg(bmap->ineq[i], bmap->div[div]+1, pos);
- isl_int_sub_ui(bmap->div[div][1], bmap->div[div][1], 1);
- isl_int_add(bmap->div[div][1],
- bmap->div[div][1], bmap->div[div][0]);
- if (!neg)
- return 0;
- if (isl_seq_first_non_zero(bmap->ineq[i]+pos+1,
- bmap->n_div-div-1) != -1)
- return 0;
- } else if (isl_int_abs_eq(bmap->ineq[i][pos], bmap->div[div][0])) {
- if (!isl_seq_eq(bmap->ineq[i], bmap->div[div]+1, pos))
- return 0;
- if (isl_seq_first_non_zero(bmap->ineq[i]+pos+1,
- bmap->n_div-div-1) != -1)
- return 0;
- } else
+ if (!isl_basic_map_is_div_constraint(bmap, bmap->ineq[i], div))
return 0;
}
}
-/* Remove any div that is defined in terms of the given variable.
+/* Remove definition of any div that is defined in terms of the given variable.
+ * The div itself is not removed. Functions such as
+ * eliminate_divs_ineq depend on the other divs remaining in place.
*/
static struct isl_basic_map *remove_dependent_vars(struct isl_basic_map *bmap,
int pos)
{
int i;
- unsigned dim = isl_dim_total(bmap->dim);
for (i = 0; i < bmap->n_div; ++i) {
if (isl_int_is_zero(bmap->div[i][0]))
continue;
if (isl_int_is_zero(bmap->div[i][1+1+pos]))
continue;
- bmap = isl_basic_map_eliminate_vars(bmap, dim + i, 1);
- if (!bmap)
- return NULL;
+ isl_int_set_si(bmap->div[i][0], 0);
}
return bmap;
}
for (i = 0; i < bmap->n_eq; ++i) {
if (isl_int_is_zero(bmap->eq[i][1+d]))
continue;
- eliminate_var_using_equality(bmap, d, bmap->eq[i], NULL);
+ eliminate_var_using_equality(bmap, d, bmap->eq[i], 0, NULL);
isl_basic_map_drop_equality(bmap, i);
break;
}
}
bmap = isl_basic_map_extend_constraints(bmap,
0, n_lower * n_upper);
+ if (!bmap)
+ goto error;
for (i = bmap->n_ineq - 1; i >= 0; --i) {
int last;
if (isl_int_is_zero(bmap->ineq[i][1+d]))
bmap = isl_basic_map_normalize_constraints(bmap);
bmap = remove_duplicate_constraints(bmap, NULL);
bmap = isl_basic_map_gauss(bmap, NULL);
- bmap = isl_basic_map_convex_hull(bmap);
+ bmap = isl_basic_map_remove_redundancies(bmap);
if (!bmap)
goto error;
if (ISL_F_ISSET(bmap, ISL_BASIC_MAP_EMPTY))
static void set_compute_elimination_index(struct isl_basic_set *bset, int *elim)
{
- return compute_elimination_index((struct isl_basic_map *)bset, elim);
+ compute_elimination_index((struct isl_basic_map *)bset, elim);
}
static int reduced_using_equalities(isl_int *dst, isl_int *src,
struct isl_basic_map *bmap, int *elim)
{
- int d, i;
+ int d;
int copied = 0;
unsigned total;
if (!bset || !context)
goto error;
+ if (context->n_eq == 0) {
+ isl_basic_set_free(context);
+ return bset;
+ }
+
bset = isl_basic_set_cow(bset);
if (!bset)
goto error;
- elim = isl_alloc_array(ctx, int, isl_basic_set_n_dim(bset));
+ elim = isl_alloc_array(bset->ctx, int, isl_basic_set_n_dim(bset));
if (!elim)
goto error;
set_compute_elimination_index(context, elim);
total = isl_basic_set_total_dim(bset);
B = isl_mat_sub_alloc(bset->ctx, bset->eq, 0, bset->n_eq, 0, 1 + total);
- C = isl_mat_variable_compression(bset->ctx, B, NULL);
+ C = isl_mat_variable_compression(B, NULL);
if (!C)
return bset;
if (C->n_col == 0) {
- isl_mat_free(bset->ctx, C);
+ isl_mat_free(C);
return isl_basic_set_set_to_empty(bset);
}
B = isl_mat_sub_alloc(bset->ctx, bset->ineq,
0, bset->n_ineq, 0, 1 + total);
- C = isl_mat_product(bset->ctx, B, C);
+ C = isl_mat_product(B, C);
if (!C)
return bset;
}
isl_int_clear(gcd);
- isl_mat_free(bset->ctx, C);
+ isl_mat_free(C);
return bset;
}
/* Remove all information from bset that is redundant in the context
- * of context. In particular, equalities that are linear combinations
- * of those in context are removed. Then the inequalities that are
- * redundant in the context of the equalities and inequalities of
- * context are removed.
+ * of context. Both bset and context are assumed to be full-dimensional.
*
- * We first simplify the constraints of "bset" in the context of the
- * equalities of "context".
- * Then we simplify the inequalities of the context in the context
- * of the equalities of bset and remove the inequalities from "bset"
+ * We first * remove the inequalities from "bset"
* that are obviously redundant with respect to some inequality in "context".
*
* If there are any inequalities left, we construct a tableau for
* the context and then add the inequalities of "bset".
- * Before adding these equalities, we freeze all constraints such that
+ * Before adding these inequalities, we freeze all constraints such that
* they won't be considered redundant in terms of the constraints of "bset".
- * Then we detect all equalities and redundant constraints (among the
- * constraints that weren't frozen) and update bset according to the results.
- * We have to be careful here because we don't want any of the context
- * constraints to remain and because we haven't added the equalities of "bset"
- * to the tableau so we temporarily have to pretend that there were no
- * equalities.
+ * Then we detect all redundant constraints (among the
+ * constraints that weren't frozen), first by checking for redundancy in the
+ * the tableau and then by checking if replacing a constraint by its negation
+ * would lead to an empty set. This last step is fairly expensive
+ * and could be optimized by more reuse of the tableau.
+ * Finally, we update bset according to the results.
*/
-static struct isl_basic_set *uset_gist(struct isl_basic_set *bset,
- struct isl_basic_set *context)
+static __isl_give isl_basic_set *uset_gist_full(__isl_take isl_basic_set *bset,
+ __isl_take isl_basic_set *context)
{
- int i;
- struct isl_tab *tab;
+ int i, k;
+ isl_basic_set *combined = NULL;
+ struct isl_tab *tab = NULL;
unsigned context_ineq;
- struct isl_basic_set *combined = NULL;
-
- if (!context || !bset)
- goto error;
+ unsigned total;
- if (context->n_eq > 0)
- bset = isl_basic_set_reduce_using_equalities(bset,
- isl_basic_set_copy(context));
- if (!bset)
+ if (!bset || !context)
goto error;
- if (isl_basic_set_fast_is_empty(bset))
- goto done;
- if (!bset->n_ineq)
- goto done;
- if (bset->n_eq > 0) {
- struct isl_basic_set *affine_hull;
- affine_hull = isl_basic_set_copy(bset);
- affine_hull = isl_basic_set_cow(affine_hull);
- if (!affine_hull)
- goto error;
- isl_basic_set_free_inequality(affine_hull, affine_hull->n_ineq);
- context = isl_basic_set_intersect(context, affine_hull);
- context = isl_basic_set_gauss(context, NULL);
- context = normalize_constraints_in_compressed_space(context);
+ if (isl_basic_set_is_universe(bset)) {
+ isl_basic_set_free(context);
+ return bset;
}
- if (!context)
- goto error;
- if (ISL_F_ISSET(context, ISL_BASIC_SET_EMPTY)) {
- isl_basic_set_free(bset);
- return context;
+
+ if (isl_basic_set_is_universe(context)) {
+ isl_basic_set_free(context);
+ return bset;
}
- if (!context->n_ineq)
- goto done;
+
bset = remove_shifted_constraints(bset, context);
- if (!bset->n_ineq)
+ if (!bset)
+ goto error;
+ if (bset->n_ineq == 0)
goto done;
- isl_basic_set_free_equality(context, context->n_eq);
+
context_ineq = context->n_ineq;
combined = isl_basic_set_cow(isl_basic_set_copy(context));
- combined = isl_basic_set_extend_constraints(combined,
- bset->n_eq, bset->n_ineq);
+ combined = isl_basic_set_extend_constraints(combined, 0, bset->n_ineq);
tab = isl_tab_from_basic_set(combined);
- if (!tab)
- goto error;
for (i = 0; i < context_ineq; ++i)
- tab->con[i].frozen = 1;
- tab = isl_tab_extend(bset->ctx, tab, bset->n_ineq);
- if (!tab)
- goto error;
+ if (isl_tab_freeze_constraint(tab, i) < 0)
+ goto error;
+ tab = isl_tab_extend(tab, bset->n_ineq);
for (i = 0; i < bset->n_ineq; ++i)
- tab = isl_tab_add_ineq(bset->ctx, tab, bset->ineq[i]);
+ if (isl_tab_add_ineq(tab, bset->ineq[i]) < 0)
+ goto error;
bset = isl_basic_set_add_constraints(combined, bset, 0);
- tab = isl_tab_detect_equalities(bset->ctx, tab);
- tab = isl_tab_detect_redundant(bset->ctx, tab);
- if (!tab)
- goto error2;
- for (i = 0; i < context_ineq; ++i) {
- tab->con[i].is_zero = 0;
+ combined = NULL;
+ if (!bset)
+ goto error;
+ if (isl_tab_detect_redundant(tab) < 0)
+ goto error;
+ total = isl_basic_set_total_dim(bset);
+ for (i = context_ineq; i < bset->n_ineq; ++i) {
+ int is_empty;
+ if (tab->con[i].is_redundant)
+ continue;
tab->con[i].is_redundant = 1;
+ combined = isl_basic_set_dup(bset);
+ combined = isl_basic_set_update_from_tab(combined, tab);
+ combined = isl_basic_set_extend_constraints(combined, 0, 1);
+ k = isl_basic_set_alloc_inequality(combined);
+ if (k < 0)
+ goto error;
+ isl_seq_neg(combined->ineq[k], bset->ineq[i], 1 + total);
+ isl_int_sub_ui(combined->ineq[k][0], combined->ineq[k][0], 1);
+ is_empty = isl_basic_set_is_empty(combined);
+ if (is_empty < 0)
+ goto error;
+ isl_basic_set_free(combined);
+ combined = NULL;
+ if (!is_empty)
+ tab->con[i].is_redundant = 0;
}
+ for (i = 0; i < context_ineq; ++i)
+ tab->con[i].is_redundant = 1;
bset = isl_basic_set_update_from_tab(bset, tab);
- isl_tab_free(bset->ctx, tab);
- ISL_F_SET(bset, ISL_BASIC_SET_NO_IMPLICIT);
- ISL_F_SET(bset, ISL_BASIC_SET_NO_REDUNDANT);
+ if (bset) {
+ ISL_F_SET(bset, ISL_BASIC_SET_NO_IMPLICIT);
+ ISL_F_SET(bset, ISL_BASIC_SET_NO_REDUNDANT);
+ }
+
+ isl_tab_free(tab);
done:
bset = isl_basic_set_simplify(bset);
bset = isl_basic_set_finalize(bset);
isl_basic_set_free(context);
return bset;
error:
+ isl_tab_free(tab);
isl_basic_set_free(combined);
-error2:
+ isl_basic_set_free(context);
+ isl_basic_set_free(bset);
+ return NULL;
+}
+
+/* Remove all information from bset that is redundant in the context
+ * of context. In particular, equalities that are linear combinations
+ * of those in context are removed. Then the inequalities that are
+ * redundant in the context of the equalities and inequalities of
+ * context are removed.
+ *
+ * We first compute the integer affine hull of the intersection,
+ * compute the gist inside this affine hull and then add back
+ * those equalities that are not implied by the context.
+ */
+static __isl_give isl_basic_set *uset_gist(__isl_take isl_basic_set *bset,
+ __isl_take isl_basic_set *context)
+{
+ isl_mat *eq;
+ isl_mat *T, *T2;
+ isl_basic_set *aff;
+ isl_basic_set *aff_context;
+ unsigned total;
+
+ if (!bset || !context)
+ goto error;
+
+ bset = isl_basic_set_intersect(bset, isl_basic_set_copy(context));
+ if (isl_basic_set_fast_is_empty(bset)) {
+ isl_basic_set_free(context);
+ return bset;
+ }
+ aff = isl_basic_set_affine_hull(isl_basic_set_copy(bset));
+ if (!aff)
+ goto error;
+ if (isl_basic_set_fast_is_empty(aff)) {
+ isl_basic_set_free(aff);
+ isl_basic_set_free(context);
+ return bset;
+ }
+ if (aff->n_eq == 0) {
+ isl_basic_set_free(aff);
+ return uset_gist_full(bset, context);
+ }
+ total = isl_basic_set_total_dim(bset);
+ eq = isl_mat_sub_alloc(bset->ctx, aff->eq, 0, aff->n_eq, 0, 1 + total);
+ eq = isl_mat_cow(eq);
+ T = isl_mat_variable_compression(eq, &T2);
+ if (T && T->n_col == 0) {
+ isl_mat_free(T);
+ isl_mat_free(T2);
+ isl_basic_set_free(context);
+ isl_basic_set_free(aff);
+ return isl_basic_set_set_to_empty(bset);
+ }
+
+ aff_context = isl_basic_set_affine_hull(isl_basic_set_copy(context));
+
+ bset = isl_basic_set_preimage(bset, isl_mat_copy(T));
+ context = isl_basic_set_preimage(context, T);
+
+ bset = uset_gist_full(bset, context);
+ bset = isl_basic_set_preimage(bset, T2);
+ bset = isl_basic_set_intersect(bset, aff);
+ bset = isl_basic_set_reduce_using_equalities(bset, aff_context);
+
+ if (bset) {
+ ISL_F_SET(bset, ISL_BASIC_SET_NO_IMPLICIT);
+ ISL_F_SET(bset, ISL_BASIC_SET_NO_REDUNDANT);
+ }
+
+ return bset;
+error:
isl_basic_set_free(bset);
isl_basic_set_free(context);
return NULL;
return bmap;
}
- bmap = isl_basic_map_convex_hull(bmap);
- context = isl_basic_map_convex_hull(context);
+ bmap = isl_basic_map_remove_redundancies(bmap);
+ context = isl_basic_map_remove_redundancies(context);
if (context->n_eq)
bmap = normalize_divs_in_context(bmap, context);
/*
* Assumes context has no implicit divs.
*/
-struct isl_map *isl_map_gist(struct isl_map *map, struct isl_basic_map *context)
+__isl_give isl_map *isl_map_gist_basic_map(__isl_take isl_map *map,
+ __isl_take isl_basic_map *context)
{
int i;
return isl_map_universe(dim);
}
- context = isl_basic_map_convex_hull(context);
+ context = isl_basic_map_remove_redundancies(context);
map = isl_map_cow(map);
if (!map || !context)
goto error;;
return NULL;
}
+__isl_give isl_map *isl_map_gist(__isl_take isl_map *map,
+ __isl_take isl_map *context)
+{
+ return isl_map_gist_basic_map(map, isl_map_convex_hull(context));
+}
+
struct isl_basic_set *isl_basic_set_gist(struct isl_basic_set *bset,
struct isl_basic_set *context)
{
(struct isl_basic_map *)bset, (struct isl_basic_map *)context);
}
-struct isl_set *isl_set_gist(struct isl_set *set, struct isl_basic_set *context)
+__isl_give isl_set *isl_set_gist_basic_set(__isl_take isl_set *set,
+ __isl_take isl_basic_set *context)
{
- return (struct isl_set *)isl_map_gist((struct isl_map *)set,
+ return (struct isl_set *)isl_map_gist_basic_map((struct isl_map *)set,
(struct isl_basic_map *)context);
}
+__isl_give isl_set *isl_set_gist(__isl_take isl_set *set,
+ __isl_take isl_set *context)
+{
+ return (struct isl_set *)isl_map_gist((struct isl_map *)set,
+ (struct isl_map *)context);
+}
+
/* Quick check to see if two basic maps are disjoint.
* In particular, we reduce the equalities and inequalities of
* one basic map in the context of the equalities of the other
struct isl_vec *v = NULL;
int *elim = NULL;
unsigned total;
- int d, i;
+ int i;
if (!bmap1 || !bmap2)
return -1;
isl_seq_first_non_zero(v->block.data + 1, total) == -1)
goto disjoint;
}
- isl_vec_free(bmap1->ctx, v);
+ isl_vec_free(v);
free(elim);
return 0;
disjoint:
- isl_vec_free(bmap1->ctx, v);
+ isl_vec_free(v);
free(elim);
return 1;
error:
- isl_vec_free(bmap1->ctx, v);
+ isl_vec_free(v);
free(elim);
return -1;
}
return isl_map_fast_is_disjoint((struct isl_map *)set1,
(struct isl_map *)set2);
}
+
+/* Check if we can combine a given div with lower bound l and upper
+ * bound u with some other div and if so return that other div.
+ * Otherwise return -1.
+ *
+ * We first check that
+ * - the bounds are opposites of each other (except for the constant
+ * term)
+ * - the bounds do not reference any other div
+ * - no div is defined in terms of this div
+ *
+ * Let m be the size of the range allowed on the div by the bounds.
+ * That is, the bounds are of the form
+ *
+ * e <= a <= e + m - 1
+ *
+ * with e some expression in the other variables.
+ * We look for another div b such that no third div is defined in terms
+ * of this second div b and such that in any constraint that contains
+ * a (except for the given lower and upper bound), also contains b
+ * with a coefficient that is m times that of b.
+ * That is, all constraints (execpt for the lower and upper bound)
+ * are of the form
+ *
+ * e + f (a + m b) >= 0
+ *
+ * If so, we return b so that "a + m b" can be replaced by
+ * a single div "c = a + m b".
+ */
+static int div_find_coalesce(struct isl_basic_map *bmap, int *pairs,
+ unsigned div, unsigned l, unsigned u)
+{
+ int i, j;
+ unsigned dim;
+ int coalesce = -1;
+
+ if (bmap->n_div <= 1)
+ return -1;
+ dim = isl_dim_total(bmap->dim);
+ if (isl_seq_first_non_zero(bmap->ineq[l] + 1 + dim, div) != -1)
+ return -1;
+ if (isl_seq_first_non_zero(bmap->ineq[l] + 1 + dim + div + 1,
+ bmap->n_div - div - 1) != -1)
+ return -1;
+ if (!isl_seq_is_neg(bmap->ineq[l] + 1, bmap->ineq[u] + 1,
+ dim + bmap->n_div))
+ return -1;
+
+ for (i = 0; i < bmap->n_div; ++i) {
+ if (isl_int_is_zero(bmap->div[i][0]))
+ continue;
+ if (!isl_int_is_zero(bmap->div[i][1 + 1 + dim + div]))
+ return -1;
+ }
+
+ isl_int_add(bmap->ineq[l][0], bmap->ineq[l][0], bmap->ineq[u][0]);
+ if (isl_int_is_neg(bmap->ineq[l][0])) {
+ isl_int_sub(bmap->ineq[l][0],
+ bmap->ineq[l][0], bmap->ineq[u][0]);
+ bmap = isl_basic_map_copy(bmap);
+ bmap = isl_basic_map_set_to_empty(bmap);
+ isl_basic_map_free(bmap);
+ return -1;
+ }
+ isl_int_add_ui(bmap->ineq[l][0], bmap->ineq[l][0], 1);
+ for (i = 0; i < bmap->n_div; ++i) {
+ if (i == div)
+ continue;
+ if (!pairs[i])
+ continue;
+ for (j = 0; j < bmap->n_div; ++j) {
+ if (isl_int_is_zero(bmap->div[j][0]))
+ continue;
+ if (!isl_int_is_zero(bmap->div[j][1 + 1 + dim + i]))
+ break;
+ }
+ if (j < bmap->n_div)
+ continue;
+ for (j = 0; j < bmap->n_ineq; ++j) {
+ int valid;
+ if (j == l || j == u)
+ continue;
+ if (isl_int_is_zero(bmap->ineq[j][1 + dim + div]))
+ continue;
+ if (isl_int_is_zero(bmap->ineq[j][1 + dim + i]))
+ break;
+ isl_int_mul(bmap->ineq[j][1 + dim + div],
+ bmap->ineq[j][1 + dim + div],
+ bmap->ineq[l][0]);
+ valid = isl_int_eq(bmap->ineq[j][1 + dim + div],
+ bmap->ineq[j][1 + dim + i]);
+ isl_int_divexact(bmap->ineq[j][1 + dim + div],
+ bmap->ineq[j][1 + dim + div],
+ bmap->ineq[l][0]);
+ if (!valid)
+ break;
+ }
+ if (j < bmap->n_ineq)
+ continue;
+ coalesce = i;
+ break;
+ }
+ isl_int_sub_ui(bmap->ineq[l][0], bmap->ineq[l][0], 1);
+ isl_int_sub(bmap->ineq[l][0], bmap->ineq[l][0], bmap->ineq[u][0]);
+ return coalesce;
+}
+
+/* Given a lower and an upper bound on div i, construct an inequality
+ * that when nonnegative ensures that this pair of bounds always allows
+ * for an integer value of the given div.
+ * The lower bound is inequality l, while the upper bound is inequality u.
+ * The constructed inequality is stored in ineq.
+ * g, fl, fu are temporary scalars.
+ *
+ * Let the upper bound be
+ *
+ * -n_u a + e_u >= 0
+ *
+ * and the lower bound
+ *
+ * n_l a + e_l >= 0
+ *
+ * Let n_u = f_u g and n_l = f_l g, with g = gcd(n_u, n_l).
+ * We have
+ *
+ * - f_u e_l <= f_u f_l g a <= f_l e_u
+ *
+ * Since all variables are integer valued, this is equivalent to
+ *
+ * - f_u e_l - (f_u - 1) <= f_u f_l g a <= f_l e_u + (f_l - 1)
+ *
+ * If this interval is at least f_u f_l g, then it contains at least
+ * one integer value for a.
+ * That is, the test constraint is
+ *
+ * f_l e_u + f_u e_l + f_l - 1 + f_u - 1 + 1 >= f_u f_l g
+ */
+static void construct_test_ineq(struct isl_basic_map *bmap, int i,
+ int l, int u, isl_int *ineq, isl_int g, isl_int fl, isl_int fu)
+{
+ unsigned dim;
+ dim = isl_dim_total(bmap->dim);
+
+ isl_int_gcd(g, bmap->ineq[l][1 + dim + i], bmap->ineq[u][1 + dim + i]);
+ isl_int_divexact(fl, bmap->ineq[l][1 + dim + i], g);
+ isl_int_divexact(fu, bmap->ineq[u][1 + dim + i], g);
+ isl_int_neg(fu, fu);
+ isl_seq_combine(ineq, fl, bmap->ineq[u], fu, bmap->ineq[l],
+ 1 + dim + bmap->n_div);
+ isl_int_add(ineq[0], ineq[0], fl);
+ isl_int_add(ineq[0], ineq[0], fu);
+ isl_int_sub_ui(ineq[0], ineq[0], 1);
+ isl_int_mul(g, g, fl);
+ isl_int_mul(g, g, fu);
+ isl_int_sub(ineq[0], ineq[0], g);
+}
+
+/* Remove more kinds of divs that are not strictly needed.
+ * In particular, if all pairs of lower and upper bounds on a div
+ * are such that they allow at least one integer value of the div,
+ * the we can eliminate the div using Fourier-Motzkin without
+ * introducing any spurious solutions.
+ */
+static struct isl_basic_map *drop_more_redundant_divs(
+ struct isl_basic_map *bmap, int *pairs, int n)
+{
+ struct isl_tab *tab = NULL;
+ struct isl_vec *vec = NULL;
+ unsigned dim;
+ int remove = -1;
+ isl_int g, fl, fu;
+
+ isl_int_init(g);
+ isl_int_init(fl);
+ isl_int_init(fu);
+
+ if (!bmap)
+ goto error;
+
+ dim = isl_dim_total(bmap->dim);
+ vec = isl_vec_alloc(bmap->ctx, 1 + dim + bmap->n_div);
+ if (!vec)
+ goto error;
+
+ tab = isl_tab_from_basic_map(bmap);
+
+ while (n > 0) {
+ int i, l, u;
+ int best = -1;
+ enum isl_lp_result res;
+
+ for (i = 0; i < bmap->n_div; ++i) {
+ if (!pairs[i])
+ continue;
+ if (best >= 0 && pairs[best] <= pairs[i])
+ continue;
+ best = i;
+ }
+
+ i = best;
+ for (l = 0; l < bmap->n_ineq; ++l) {
+ if (!isl_int_is_pos(bmap->ineq[l][1 + dim + i]))
+ continue;
+ for (u = 0; u < bmap->n_ineq; ++u) {
+ if (!isl_int_is_neg(bmap->ineq[u][1 + dim + i]))
+ continue;
+ construct_test_ineq(bmap, i, l, u,
+ vec->el, g, fl, fu);
+ res = isl_tab_min(tab, vec->el,
+ bmap->ctx->one, &g, NULL, 0);
+ if (res == isl_lp_error)
+ goto error;
+ if (res == isl_lp_empty) {
+ bmap = isl_basic_map_set_to_empty(bmap);
+ break;
+ }
+ if (res != isl_lp_ok || isl_int_is_neg(g))
+ break;
+ }
+ if (u < bmap->n_ineq)
+ break;
+ }
+ if (l == bmap->n_ineq) {
+ remove = i;
+ break;
+ }
+ pairs[i] = 0;
+ --n;
+ }
+
+ isl_tab_free(tab);
+ isl_vec_free(vec);
+
+ isl_int_clear(g);
+ isl_int_clear(fl);
+ isl_int_clear(fu);
+
+ free(pairs);
+
+ if (remove < 0)
+ return bmap;
+
+ bmap = isl_basic_map_remove(bmap, isl_dim_div, remove, 1);
+ return isl_basic_map_drop_redundant_divs(bmap);
+error:
+ free(pairs);
+ isl_basic_map_free(bmap);
+ isl_tab_free(tab);
+ isl_vec_free(vec);
+ isl_int_clear(g);
+ isl_int_clear(fl);
+ isl_int_clear(fu);
+ return NULL;
+}
+
+/* Given a pair of divs div1 and div2 such that, expect for the lower bound l
+ * and the upper bound u, div1 always occurs together with div2 in the form
+ * (div1 + m div2), where m is the constant range on the variable div1
+ * allowed by l and u, replace the pair div1 and div2 by a single
+ * div that is equal to div1 + m div2.
+ *
+ * The new div will appear in the location that contains div2.
+ * We need to modify all constraints that contain
+ * div2 = (div - div1) / m
+ * (If a constraint does not contain div2, it will also not contain div1.)
+ * If the constraint also contains div1, then we know they appear
+ * as f (div1 + m div2) and we can simply replace (div1 + m div2) by div,
+ * i.e., the coefficient of div is f.
+ *
+ * Otherwise, we first need to introduce div1 into the constraint.
+ * Let the l be
+ *
+ * div1 + f >=0
+ *
+ * and u
+ *
+ * -div1 + f' >= 0
+ *
+ * A lower bound on div2
+ *
+ * n div2 + t >= 0
+ *
+ * can be replaced by
+ *
+ * (n * (m div 2 + div1) + m t + n f)/g >= 0
+ *
+ * with g = gcd(m,n).
+ * An upper bound
+ *
+ * -n div2 + t >= 0
+ *
+ * can be replaced by
+ *
+ * (-n * (m div2 + div1) + m t + n f')/g >= 0
+ *
+ * These constraint are those that we would obtain from eliminating
+ * div1 using Fourier-Motzkin.
+ *
+ * After all constraints have been modified, we drop the lower and upper
+ * bound and then drop div1.
+ */
+static struct isl_basic_map *coalesce_divs(struct isl_basic_map *bmap,
+ unsigned div1, unsigned div2, unsigned l, unsigned u)
+{
+ isl_int a;
+ isl_int b;
+ isl_int m;
+ unsigned dim, total;
+ int i;
+
+ dim = isl_dim_total(bmap->dim);
+ total = 1 + dim + bmap->n_div;
+
+ isl_int_init(a);
+ isl_int_init(b);
+ isl_int_init(m);
+ isl_int_add(m, bmap->ineq[l][0], bmap->ineq[u][0]);
+ isl_int_add_ui(m, m, 1);
+
+ for (i = 0; i < bmap->n_ineq; ++i) {
+ if (i == l || i == u)
+ continue;
+ if (isl_int_is_zero(bmap->ineq[i][1 + dim + div2]))
+ continue;
+ if (isl_int_is_zero(bmap->ineq[i][1 + dim + div1])) {
+ isl_int_gcd(b, m, bmap->ineq[i][1 + dim + div2]);
+ isl_int_divexact(a, m, b);
+ isl_int_divexact(b, bmap->ineq[i][1 + dim + div2], b);
+ if (isl_int_is_pos(b)) {
+ isl_seq_combine(bmap->ineq[i], a, bmap->ineq[i],
+ b, bmap->ineq[l], total);
+ } else {
+ isl_int_neg(b, b);
+ isl_seq_combine(bmap->ineq[i], a, bmap->ineq[i],
+ b, bmap->ineq[u], total);
+ }
+ }
+ isl_int_set(bmap->ineq[i][1 + dim + div2],
+ bmap->ineq[i][1 + dim + div1]);
+ isl_int_set_si(bmap->ineq[i][1 + dim + div1], 0);
+ }
+
+ isl_int_clear(a);
+ isl_int_clear(b);
+ isl_int_clear(m);
+ if (l > u) {
+ isl_basic_map_drop_inequality(bmap, l);
+ isl_basic_map_drop_inequality(bmap, u);
+ } else {
+ isl_basic_map_drop_inequality(bmap, u);
+ isl_basic_map_drop_inequality(bmap, l);
+ }
+ bmap = isl_basic_map_drop_div(bmap, div1);
+ return bmap;
+}
+
+/* First check if we can coalesce any pair of divs and
+ * then continue with dropping more redundant divs.
+ *
+ * We loop over all pairs of lower and upper bounds on a div
+ * with coefficient 1 and -1, respectively, check if there
+ * is any other div "c" with which we can coalesce the div
+ * and if so, perform the coalescing.
+ */
+static struct isl_basic_map *coalesce_or_drop_more_redundant_divs(
+ struct isl_basic_map *bmap, int *pairs, int n)
+{
+ int i, l, u;
+ unsigned dim;
+
+ dim = isl_dim_total(bmap->dim);
+
+ for (i = 0; i < bmap->n_div; ++i) {
+ if (!pairs[i])
+ continue;
+ for (l = 0; l < bmap->n_ineq; ++l) {
+ if (!isl_int_is_one(bmap->ineq[l][1 + dim + i]))
+ continue;
+ for (u = 0; u < bmap->n_ineq; ++u) {
+ int c;
+
+ if (!isl_int_is_negone(bmap->ineq[u][1+dim+i]))
+ continue;
+ c = div_find_coalesce(bmap, pairs, i, l, u);
+ if (c < 0)
+ continue;
+ free(pairs);
+ bmap = coalesce_divs(bmap, i, c, l, u);
+ return isl_basic_map_drop_redundant_divs(bmap);
+ }
+ }
+ }
+
+ if (ISL_F_ISSET(bmap, ISL_BASIC_MAP_EMPTY))
+ return bmap;
+
+ return drop_more_redundant_divs(bmap, pairs, n);
+}
+
+/* Remove divs that are not strictly needed.
+ * In particular, if a div only occurs positively (or negatively)
+ * in constraints, then it can simply be dropped.
+ * Also, if a div occurs only occurs in two constraints and if moreover
+ * those two constraints are opposite to each other, except for the constant
+ * term and if the sum of the constant terms is such that for any value
+ * of the other values, there is always at least one integer value of the
+ * div, i.e., if one plus this sum is greater than or equal to
+ * the (absolute value) of the coefficent of the div in the constraints,
+ * then we can also simply drop the div.
+ *
+ * If any divs are left after these simple checks then we move on
+ * to more complicated cases in drop_more_redundant_divs.
+ */
+struct isl_basic_map *isl_basic_map_drop_redundant_divs(
+ struct isl_basic_map *bmap)
+{
+ int i, j;
+ unsigned off;
+ int *pairs = NULL;
+ int n = 0;
+
+ if (!bmap)
+ goto error;
+
+ off = isl_dim_total(bmap->dim);
+ pairs = isl_calloc_array(bmap->ctx, int, bmap->n_div);
+ if (!pairs)
+ goto error;
+
+ for (i = 0; i < bmap->n_div; ++i) {
+ int pos, neg;
+ int last_pos, last_neg;
+ int redundant;
+ int defined;
+
+ defined = !isl_int_is_zero(bmap->div[i][0]);
+ for (j = 0; j < bmap->n_eq; ++j)
+ if (!isl_int_is_zero(bmap->eq[j][1 + off + i]))
+ break;
+ if (j < bmap->n_eq)
+ continue;
+ ++n;
+ pos = neg = 0;
+ for (j = 0; j < bmap->n_ineq; ++j) {
+ if (isl_int_is_pos(bmap->ineq[j][1 + off + i])) {
+ last_pos = j;
+ ++pos;
+ }
+ if (isl_int_is_neg(bmap->ineq[j][1 + off + i])) {
+ last_neg = j;
+ ++neg;
+ }
+ }
+ pairs[i] = pos * neg;
+ if (pairs[i] == 0) {
+ for (j = bmap->n_ineq - 1; j >= 0; --j)
+ if (!isl_int_is_zero(bmap->ineq[j][1+off+i]))
+ isl_basic_map_drop_inequality(bmap, j);
+ bmap = isl_basic_map_drop_div(bmap, i);
+ free(pairs);
+ return isl_basic_map_drop_redundant_divs(bmap);
+ }
+ if (pairs[i] != 1)
+ continue;
+ if (!isl_seq_is_neg(bmap->ineq[last_pos] + 1,
+ bmap->ineq[last_neg] + 1,
+ off + bmap->n_div))
+ continue;
+
+ isl_int_add(bmap->ineq[last_pos][0],
+ bmap->ineq[last_pos][0], bmap->ineq[last_neg][0]);
+ isl_int_add_ui(bmap->ineq[last_pos][0],
+ bmap->ineq[last_pos][0], 1);
+ redundant = isl_int_ge(bmap->ineq[last_pos][0],
+ bmap->ineq[last_pos][1+off+i]);
+ isl_int_sub_ui(bmap->ineq[last_pos][0],
+ bmap->ineq[last_pos][0], 1);
+ isl_int_sub(bmap->ineq[last_pos][0],
+ bmap->ineq[last_pos][0], bmap->ineq[last_neg][0]);
+ if (!redundant) {
+ if (defined ||
+ !ok_to_set_div_from_bound(bmap, i, last_pos)) {
+ pairs[i] = 0;
+ --n;
+ continue;
+ }
+ bmap = set_div_from_lower_bound(bmap, i, last_pos);
+ bmap = isl_basic_map_simplify(bmap);
+ free(pairs);
+ return isl_basic_map_drop_redundant_divs(bmap);
+ }
+ if (last_pos > last_neg) {
+ isl_basic_map_drop_inequality(bmap, last_pos);
+ isl_basic_map_drop_inequality(bmap, last_neg);
+ } else {
+ isl_basic_map_drop_inequality(bmap, last_neg);
+ isl_basic_map_drop_inequality(bmap, last_pos);
+ }
+ bmap = isl_basic_map_drop_div(bmap, i);
+ free(pairs);
+ return isl_basic_map_drop_redundant_divs(bmap);
+ }
+
+ if (n > 0)
+ return coalesce_or_drop_more_redundant_divs(bmap, pairs, n);
+
+ free(pairs);
+ return bmap;
+error:
+ free(pairs);
+ isl_basic_map_free(bmap);
+ return NULL;
+}
+
+struct isl_basic_set *isl_basic_set_drop_redundant_divs(
+ struct isl_basic_set *bset)
+{
+ return (struct isl_basic_set *)
+ isl_basic_map_drop_redundant_divs((struct isl_basic_map *)bset);
+}
+
+struct isl_map *isl_map_drop_redundant_divs(struct isl_map *map)
+{
+ int i;
+
+ if (!map)
+ return NULL;
+ for (i = 0; i < map->n; ++i) {
+ map->p[i] = isl_basic_map_drop_redundant_divs(map->p[i]);
+ if (!map->p[i])
+ goto error;
+ }
+ ISL_F_CLR(map, ISL_MAP_NORMALIZED);
+ return map;
+error:
+ isl_map_free(map);
+ return NULL;
+}
+
+struct isl_set *isl_set_drop_redundant_divs(struct isl_set *set)
+{
+ return (struct isl_set *)
+ isl_map_drop_redundant_divs((struct isl_map *)set);
+}
projects / platform / upstream / isl.git / blobdiff