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isl_coalesce.c
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/*
* Copyright 2008-2009 Katholieke Universiteit Leuven
* Copyright 2010 INRIA Saclay
* Copyright 2012-2013 Ecole Normale Superieure
* Copyright 2014 INRIA Rocquencourt
*
* Use of this software is governed by the MIT license
*
* Written by Sven Verdoolaege, K.U.Leuven, Departement
* Computerwetenschappen, Celestijnenlaan 200A, B-3001 Leuven, Belgium
* and INRIA Saclay - Ile-de-France, Parc Club Orsay Universite,
* ZAC des vignes, 4 rue Jacques Monod, 91893 Orsay, France
* and Ecole Normale Superieure, 45 rue d’Ulm, 75230 Paris, France
* and Inria Paris - Rocquencourt, Domaine de Voluceau - Rocquencourt,
* B.P. 105 - 78153 Le Chesnay, France
*/
#include "isl_map_private.h"
#include <isl_seq.h>
#include <isl/options.h>
#include "isl_tab.h"
#include <isl_mat_private.h>
#include <isl_local_space_private.h>
#include <isl_vec_private.h>
#include <isl_aff_private.h>
#define STATUS_ERROR -1
#define STATUS_REDUNDANT 1
#define STATUS_VALID 2
#define STATUS_SEPARATE 3
#define STATUS_CUT 4
#define STATUS_ADJ_EQ 5
#define STATUS_ADJ_INEQ 6
static int status_in(isl_int *ineq, struct isl_tab *tab)
{
enum isl_ineq_type type = isl_tab_ineq_type(tab, ineq);
switch (type) {
default:
case isl_ineq_error: return STATUS_ERROR;
case isl_ineq_redundant: return STATUS_VALID;
case isl_ineq_separate: return STATUS_SEPARATE;
case isl_ineq_cut: return STATUS_CUT;
case isl_ineq_adj_eq: return STATUS_ADJ_EQ;
case isl_ineq_adj_ineq: return STATUS_ADJ_INEQ;
}
}
/* Compute the position of the equalities of basic map "bmap_i"
* with respect to the basic map represented by "tab_j".
* The resulting array has twice as many entries as the number
* of equalities corresponding to the two inequalties to which
* each equality corresponds.
*/
static int *eq_status_in(__isl_keep isl_basic_map *bmap_i,
struct isl_tab *tab_j)
{
int k, l;
int *eq = isl_calloc_array(bmap_i->ctx, int, 2 * bmap_i->n_eq);
unsigned dim;
if (!eq)
return NULL;
dim = isl_basic_map_total_dim(bmap_i);
for (k = 0; k < bmap_i->n_eq; ++k) {
for (l = 0; l < 2; ++l) {
isl_seq_neg(bmap_i->eq[k], bmap_i->eq[k], 1+dim);
eq[2 * k + l] = status_in(bmap_i->eq[k], tab_j);
if (eq[2 * k + l] == STATUS_ERROR)
goto error;
}
if (eq[2 * k] == STATUS_SEPARATE ||
eq[2 * k + 1] == STATUS_SEPARATE)
break;
}
return eq;
error:
free(eq);
return NULL;
}
/* Compute the position of the inequalities of basic map "bmap_i"
* (also represented by "tab_i", if not NULL) with respect to the basic map
* represented by "tab_j".
*/
static int *ineq_status_in(__isl_keep isl_basic_map *bmap_i,
struct isl_tab *tab_i, struct isl_tab *tab_j)
{
int k;
unsigned n_eq = bmap_i->n_eq;
int *ineq = isl_calloc_array(bmap_i->ctx, int, bmap_i->n_ineq);
if (!ineq)
return NULL;
for (k = 0; k < bmap_i->n_ineq; ++k) {
if (tab_i && isl_tab_is_redundant(tab_i, n_eq + k)) {
ineq[k] = STATUS_REDUNDANT;
continue;
}
ineq[k] = status_in(bmap_i->ineq[k], tab_j);
if (ineq[k] == STATUS_ERROR)
goto error;
if (ineq[k] == STATUS_SEPARATE)
break;
}
return ineq;
error:
free(ineq);
return NULL;
}
static int any(int *con, unsigned len, int status)
{
int i;
for (i = 0; i < len ; ++i)
if (con[i] == status)
return 1;
return 0;
}
static int count(int *con, unsigned len, int status)
{
int i;
int c = 0;
for (i = 0; i < len ; ++i)
if (con[i] == status)
c++;
return c;
}
static int all(int *con, unsigned len, int status)
{
int i;
for (i = 0; i < len ; ++i) {
if (con[i] == STATUS_REDUNDANT)
continue;
if (con[i] != status)
return 0;
}
return 1;
}
/* Internal information associated to a basic map in a map
* that is to be coalesced by isl_map_coalesce.
*
* "bmap" is the basic map itself (or NULL if "removed" is set)
* "tab" is the corresponding tableau (or NULL if "removed" is set)
* "hull_hash" identifies the affine space in which "bmap" lives.
* "removed" is set if this basic map has been removed from the map
* "simplify" is set if this basic map may have some unknown integer
* divisions that were not present in the input basic maps. The basic
* map should then be simplified such that we may be able to find
* a definition among the constraints.
*
* "eq" and "ineq" are only set if we are currently trying to coalesce
* this basic map with another basic map, in which case they represent
* the position of the inequalities of this basic map with respect to
* the other basic map. The number of elements in the "eq" array
* is twice the number of equalities in the "bmap", corresponding
* to the two inequalities that make up each equality.
*/
struct isl_coalesce_info {
isl_basic_map *bmap;
struct isl_tab *tab;
uint32_t hull_hash;
int removed;
int simplify;
int *eq;
int *ineq;
};
/* Compute the hash of the (apparent) affine hull of info->bmap (with
* the existentially quantified variables removed) and store it
* in info->hash.
*/
static int coalesce_info_set_hull_hash(struct isl_coalesce_info *info)
{
isl_basic_map *hull;
unsigned n_div;
hull = isl_basic_map_copy(info->bmap);
hull = isl_basic_map_plain_affine_hull(hull);
n_div = isl_basic_map_dim(hull, isl_dim_div);
hull = isl_basic_map_drop_constraints_involving_dims(hull,
isl_dim_div, 0, n_div);
info->hull_hash = isl_basic_map_get_hash(hull);
isl_basic_map_free(hull);
return hull ? 0 : -1;
}
/* Free all the allocated memory in an array
* of "n" isl_coalesce_info elements.
*/
static void clear_coalesce_info(int n, struct isl_coalesce_info *info)
{
int i;
if (!info)
return;
for (i = 0; i < n; ++i) {
isl_basic_map_free(info[i].bmap);
isl_tab_free(info[i].tab);
}
free(info);
}
/* Drop the basic map represented by "info".
* That is, clear the memory associated to the entry and
* mark it as having been removed.
*/
static void drop(struct isl_coalesce_info *info)
{
info->bmap = isl_basic_map_free(info->bmap);
isl_tab_free(info->tab);
info->tab = NULL;
info->removed = 1;
}
/* Exchange the information in "info1" with that in "info2".
*/
static void exchange(struct isl_coalesce_info *info1,
struct isl_coalesce_info *info2)
{
struct isl_coalesce_info info;
info = *info1;
*info1 = *info2;
*info2 = info;
}
/* This type represents the kind of change that has been performed
* while trying to coalesce two basic maps.
*
* isl_change_none: nothing was changed
* isl_change_drop_first: the first basic map was removed
* isl_change_drop_second: the second basic map was removed
* isl_change_fuse: the two basic maps were replaced by a new basic map.
*/
enum isl_change {
isl_change_error = -1,
isl_change_none = 0,
isl_change_drop_first,
isl_change_drop_second,
isl_change_fuse,
};
/* Update "change" based on an interchange of the first and the second
* basic map. That is, interchange isl_change_drop_first and
* isl_change_drop_second.
*/
static enum isl_change invert_change(enum isl_change change)
{
switch (change) {
case isl_change_error:
return isl_change_error;
case isl_change_none:
return isl_change_none;
case isl_change_drop_first:
return isl_change_drop_second;
case isl_change_drop_second:
return isl_change_drop_first;
case isl_change_fuse:
return isl_change_fuse;
}
}
/* Add the valid constraints of the basic map represented by "info"
* to "bmap". "len" is the size of the constraints.
* If only one of the pair of inequalities that make up an equality
* is valid, then add that inequality.
*/
static __isl_give isl_basic_map *add_valid_constraints(
__isl_take isl_basic_map *bmap, struct isl_coalesce_info *info,
unsigned len)
{
int k, l;
if (!bmap)
return NULL;
for (k = 0; k < info->bmap->n_eq; ++k) {
if (info->eq[2 * k] == STATUS_VALID &&
info->eq[2 * k + 1] == STATUS_VALID) {
l = isl_basic_map_alloc_equality(bmap);
if (l < 0)
return isl_basic_map_free(bmap);
isl_seq_cpy(bmap->eq[l], info->bmap->eq[k], len);
} else if (info->eq[2 * k] == STATUS_VALID) {
l = isl_basic_map_alloc_inequality(bmap);
if (l < 0)
return isl_basic_map_free(bmap);
isl_seq_neg(bmap->ineq[l], info->bmap->eq[k], len);
} else if (info->eq[2 * k + 1] == STATUS_VALID) {
l = isl_basic_map_alloc_inequality(bmap);
if (l < 0)
return isl_basic_map_free(bmap);
isl_seq_cpy(bmap->ineq[l], info->bmap->eq[k], len);
}
}
for (k = 0; k < info->bmap->n_ineq; ++k) {
if (info->ineq[k] != STATUS_VALID)
continue;
l = isl_basic_map_alloc_inequality(bmap);
if (l < 0)
return isl_basic_map_free(bmap);
isl_seq_cpy(bmap->ineq[l], info->bmap->ineq[k], len);
}
return bmap;
}
/* Is "bmap" defined by a number of (non-redundant) constraints that
* is greater than the number of constraints of basic maps i and j combined?
* Equalities are counted as two inequalities.
*/
static int number_of_constraints_increases(int i, int j,
struct isl_coalesce_info *info,
__isl_keep isl_basic_map *bmap, struct isl_tab *tab)
{
int k, n_old, n_new;
n_old = 2 * info[i].bmap->n_eq + info[i].bmap->n_ineq;
n_old += 2 * info[j].bmap->n_eq + info[j].bmap->n_ineq;
n_new = 2 * bmap->n_eq;
for (k = 0; k < bmap->n_ineq; ++k)
if (!isl_tab_is_redundant(tab, bmap->n_eq + k))
++n_new;
return n_new > n_old;
}
/* Replace the pair of basic maps i and j by the basic map bounded
* by the valid constraints in both basic maps and the constraints
* in extra (if not NULL).
* Place the fused basic map in the position that is the smallest of i and j.
*
* If "detect_equalities" is set, then look for equalities encoded
* as pairs of inequalities.
* If "check_number" is set, then the original basic maps are only
* replaced if the total number of constraints does not increase.
* While the number of integer divisions in the two basic maps
* is assumed to be the same, the actual definitions may be different.
* We only copy the definition from one of the basic map if it is
* the same as that of the other basic map. Otherwise, we mark
* the integer division as unknown and schedule for the basic map
* to be simplified in an attempt to recover the integer division definition.
*/
static enum isl_change fuse(int i, int j, struct isl_coalesce_info *info,
__isl_keep isl_mat *extra, int detect_equalities, int check_number)
{
int k, l;
struct isl_basic_map *fused = NULL;
struct isl_tab *fused_tab = NULL;
unsigned total = isl_basic_map_total_dim(info[i].bmap);
unsigned extra_rows = extra ? extra->n_row : 0;
unsigned n_eq, n_ineq;
if (j < i)
return fuse(j, i, info, extra, detect_equalities, check_number);
n_eq = info[i].bmap->n_eq + info[j].bmap->n_eq;
n_ineq = info[i].bmap->n_ineq + info[j].bmap->n_ineq;
fused = isl_basic_map_alloc_space(isl_space_copy(info[i].bmap->dim),
info[i].bmap->n_div, n_eq, n_eq + n_ineq + extra_rows);
fused = add_valid_constraints(fused, &info[i], 1 + total);
fused = add_valid_constraints(fused, &info[j], 1 + total);
if (!fused)
goto error;
for (k = 0; k < info[i].bmap->n_div; ++k) {
int l = isl_basic_map_alloc_div(fused);
if (l < 0)
goto error;
if (isl_seq_eq(info[i].bmap->div[k], info[j].bmap->div[k],
1 + 1 + total)) {
isl_seq_cpy(fused->div[l], info[i].bmap->div[k],
1 + 1 + total);
} else {
isl_int_set_si(fused->div[l][0], 0);
info[i].simplify = 1;
}
}
for (k = 0; k < extra_rows; ++k) {
l = isl_basic_map_alloc_inequality(fused);
if (l < 0)
goto error;
isl_seq_cpy(fused->ineq[l], extra->row[k], 1 + total);
}
if (detect_equalities)
fused = isl_basic_map_detect_inequality_pairs(fused, NULL);
fused = isl_basic_map_gauss(fused, NULL);
ISL_F_SET(fused, ISL_BASIC_MAP_FINAL);
if (ISL_F_ISSET(info[i].bmap, ISL_BASIC_MAP_RATIONAL) &&
ISL_F_ISSET(info[j].bmap, ISL_BASIC_MAP_RATIONAL))
ISL_F_SET(fused, ISL_BASIC_MAP_RATIONAL);
fused_tab = isl_tab_from_basic_map(fused, 0);
if (isl_tab_detect_redundant(fused_tab) < 0)
goto error;
if (check_number &&
number_of_constraints_increases(i, j, info, fused, fused_tab)) {
isl_tab_free(fused_tab);
isl_basic_map_free(fused);
return isl_change_none;
}
info[i].simplify |= info[j].simplify;
isl_basic_map_free(info[i].bmap);
info[i].bmap = fused;
isl_tab_free(info[i].tab);
info[i].tab = fused_tab;
drop(&info[j]);
return isl_change_fuse;
error:
isl_tab_free(fused_tab);
isl_basic_map_free(fused);
return isl_change_error;
}
/* Given a pair of basic maps i and j such that all constraints are either
* "valid" or "cut", check if the facets corresponding to the "cut"
* constraints of i lie entirely within basic map j.
* If so, replace the pair by the basic map consisting of the valid
* constraints in both basic maps.
* Checking whether the facet lies entirely within basic map j
* is performed by checking whether the constraints of basic map j
* are valid for the facet. These tests are performed on a rational
* tableau to avoid the theoretical possibility that a constraint
* that was considered to be a cut constraint for the entire basic map i
* happens to be considered to be a valid constraint for the facet,
* even though it cuts off the same rational points.
*
* To see that we are not introducing any extra points, call the
* two basic maps A and B and the resulting map U and let x
* be an element of U \setminus ( A \cup B ).
* A line connecting x with an element of A \cup B meets a facet F
* of either A or B. Assume it is a facet of B and let c_1 be
* the corresponding facet constraint. We have c_1(x) < 0 and
* so c_1 is a cut constraint. This implies that there is some
* (possibly rational) point x' satisfying the constraints of A
* and the opposite of c_1 as otherwise c_1 would have been marked
* valid for A. The line connecting x and x' meets a facet of A
* in a (possibly rational) point that also violates c_1, but this
* is impossible since all cut constraints of B are valid for all
* cut facets of A.
* In case F is a facet of A rather than B, then we can apply the
* above reasoning to find a facet of B separating x from A \cup B first.
*/
static enum isl_change check_facets(int i, int j,
struct isl_coalesce_info *info)
{
int k, l;
struct isl_tab_undo *snap, *snap2;
unsigned n_eq = info[i].bmap->n_eq;
snap = isl_tab_snap(info[i].tab);
if (isl_tab_mark_rational(info[i].tab) < 0)
return isl_change_error;
snap2 = isl_tab_snap(info[i].tab);
for (k = 0; k < info[i].bmap->n_ineq; ++k) {
if (info[i].ineq[k] != STATUS_CUT)
continue;
if (isl_tab_select_facet(info[i].tab, n_eq + k) < 0)
return isl_change_error;
for (l = 0; l < info[j].bmap->n_ineq; ++l) {
int stat;
if (info[j].ineq[l] != STATUS_CUT)
continue;
stat = status_in(info[j].bmap->ineq[l], info[i].tab);
if (stat != STATUS_VALID)
break;
}
if (isl_tab_rollback(info[i].tab, snap2) < 0)
return isl_change_error;
if (l < info[j].bmap->n_ineq)
break;
}
if (k < info[i].bmap->n_ineq) {
if (isl_tab_rollback(info[i].tab, snap) < 0)
return isl_change_error;
return isl_change_none;
}
return fuse(i, j, info, NULL, 0, 0);
}
/* Check if info->bmap contains the basic map represented
* by the tableau "tab".
* For each equality, we check both the constraint itself
* (as an inequality) and its negation. Make sure the
* equality is returned to its original state before returning.
*/
static int contains(struct isl_coalesce_info *info, struct isl_tab *tab)
{
int k;
unsigned dim;
isl_basic_map *bmap = info->bmap;
dim = isl_basic_map_total_dim(bmap);
for (k = 0; k < bmap->n_eq; ++k) {
int stat;
isl_seq_neg(bmap->eq[k], bmap->eq[k], 1 + dim);
stat = status_in(bmap->eq[k], tab);
isl_seq_neg(bmap->eq[k], bmap->eq[k], 1 + dim);
if (stat != STATUS_VALID)
return 0;
stat = status_in(bmap->eq[k], tab);
if (stat != STATUS_VALID)
return 0;
}
for (k = 0; k < bmap->n_ineq; ++k) {
int stat;
if (info->ineq[k] == STATUS_REDUNDANT)
continue;
stat = status_in(bmap->ineq[k], tab);
if (stat != STATUS_VALID)
return 0;
}
return 1;
}
/* Basic map "i" has an inequality (say "k") that is adjacent
* to some inequality of basic map "j". All the other inequalities
* are valid for "j".
* Check if basic map "j" forms an extension of basic map "i".
*
* Note that this function is only called if some of the equalities or
* inequalities of basic map "j" do cut basic map "i". The function is
* correct even if there are no such cut constraints, but in that case
* the additional checks performed by this function are overkill.
*
* In particular, we replace constraint k, say f >= 0, by constraint
* f <= -1, add the inequalities of "j" that are valid for "i"
* and check if the result is a subset of basic map "j".
* If so, then we know that this result is exactly equal to basic map "j"
* since all its constraints are valid for basic map "j".
* By combining the valid constraints of "i" (all equalities and all
* inequalities except "k") and the valid constraints of "j" we therefore
* obtain a basic map that is equal to their union.
* In this case, there is no need to perform a rollback of the tableau
* since it is going to be destroyed in fuse().
*
*
* |\__ |\__
* | \__ | \__
* | \_ => | \__
* |_______| _ |_________\
*
*
* |\ |\
* | \ | \
* | \ | \
* | | | \
* | ||\ => | \
* | || \ | \
* | || | | |
* |__||_/ |_____/
*/
static enum isl_change is_adj_ineq_extension(int i, int j,
struct isl_coalesce_info *info)
{
int k;
struct isl_tab_undo *snap;
unsigned n_eq = info[i].bmap->n_eq;
unsigned total = isl_basic_map_total_dim(info[i].bmap);
int r;
if (isl_tab_extend_cons(info[i].tab, 1 + info[j].bmap->n_ineq) < 0)
return isl_change_error;
for (k = 0; k < info[i].bmap->n_ineq; ++k)
if (info[i].ineq[k] == STATUS_ADJ_INEQ)
break;
if (k >= info[i].bmap->n_ineq)
isl_die(isl_basic_map_get_ctx(info[i].bmap), isl_error_internal,
"info[i].ineq should have exactly one STATUS_ADJ_INEQ",
return isl_change_error);
snap = isl_tab_snap(info[i].tab);
if (isl_tab_unrestrict(info[i].tab, n_eq + k) < 0)
return isl_change_error;
isl_seq_neg(info[i].bmap->ineq[k], info[i].bmap->ineq[k], 1 + total);
isl_int_sub_ui(info[i].bmap->ineq[k][0], info[i].bmap->ineq[k][0], 1);
r = isl_tab_add_ineq(info[i].tab, info[i].bmap->ineq[k]);
isl_seq_neg(info[i].bmap->ineq[k], info[i].bmap->ineq[k], 1 + total);
isl_int_sub_ui(info[i].bmap->ineq[k][0], info[i].bmap->ineq[k][0], 1);
if (r < 0)
return isl_change_error;
for (k = 0; k < info[j].bmap->n_ineq; ++k) {
if (info[j].ineq[k] != STATUS_VALID)
continue;
if (isl_tab_add_ineq(info[i].tab, info[j].bmap->ineq[k]) < 0)
return isl_change_error;
}
if (contains(&info[j], info[i].tab))
return fuse(i, j, info, NULL, 0, 0);
if (isl_tab_rollback(info[i].tab, snap) < 0)
return isl_change_error;
return isl_change_none;
}
/* Both basic maps have at least one inequality with and adjacent
* (but opposite) inequality in the other basic map.
* Check that there are no cut constraints and that there is only
* a single pair of adjacent inequalities.
* If so, we can replace the pair by a single basic map described
* by all but the pair of adjacent inequalities.
* Any additional points introduced lie strictly between the two
* adjacent hyperplanes and can therefore be integral.
*
* ____ _____
* / ||\ / \
* / || \ / \
* \ || \ => \ \
* \ || / \ /
* \___||_/ \_____/
*
* The test for a single pair of adjancent inequalities is important
* for avoiding the combination of two basic maps like the following
*
* /|
* / |
* /__|
* _____
* | |
* | |
* |___|
*
* If there are some cut constraints on one side, then we may
* still be able to fuse the two basic maps, but we need to perform
* some additional checks in is_adj_ineq_extension.
*/
static enum isl_change check_adj_ineq(int i, int j,
struct isl_coalesce_info *info)
{
int count_i, count_j;
int cut_i, cut_j;
count_i = count(info[i].ineq, info[i].bmap->n_ineq, STATUS_ADJ_INEQ);
count_j = count(info[j].ineq, info[j].bmap->n_ineq, STATUS_ADJ_INEQ);
if (count_i != 1 && count_j != 1)
return isl_change_none;
cut_i = any(info[i].eq, 2 * info[i].bmap->n_eq, STATUS_CUT) ||
any(info[i].ineq, info[i].bmap->n_ineq, STATUS_CUT);
cut_j = any(info[j].eq, 2 * info[j].bmap->n_eq, STATUS_CUT) ||
any(info[j].ineq, info[j].bmap->n_ineq, STATUS_CUT);
if (!cut_i && !cut_j && count_i == 1 && count_j == 1)
return fuse(i, j, info, NULL, 0, 0);
if (count_i == 1 && !cut_i)
return is_adj_ineq_extension(i, j, info);
if (count_j == 1 && !cut_j)
return is_adj_ineq_extension(j, i, info);
return isl_change_none;
}
/* Basic map "i" has an inequality "k" that is adjacent to some equality
* of basic map "j". All the other inequalities are valid for "j".
* Check if basic map "j" forms an extension of basic map "i".
*
* In particular, we relax constraint "k", compute the corresponding
* facet and check whether it is included in the other basic map.
* If so, we know that relaxing the constraint extends the basic
* map with exactly the other basic map (we already know that this
* other basic map is included in the extension, because there
* were no "cut" inequalities in "i") and we can replace the
* two basic maps by this extension.
* Each integer division that does not have exactly the same
* definition in "i" and "j" is marked unknown and the basic map
* is scheduled to be simplified in an attempt to recover
* the integer division definition.
* Place this extension in the position that is the smallest of i and j.
* ____ _____
* / || / |
* / || / |
* \ || => \ |
* \ || \ |
* \___|| \____|
*/
static enum isl_change is_adj_eq_extension(int i, int j, int k,
struct isl_coalesce_info *info)
{
int change = isl_change_none;
int super;
struct isl_tab_undo *snap, *snap2;
unsigned n_eq = info[i].bmap->n_eq;
if (isl_tab_is_equality(info[i].tab, n_eq + k))
return isl_change_none;
snap = isl_tab_snap(info[i].tab);
if (isl_tab_relax(info[i].tab, n_eq + k) < 0)
return isl_change_error;
snap2 = isl_tab_snap(info[i].tab);
if (isl_tab_select_facet(info[i].tab, n_eq + k) < 0)
return isl_change_error;
super = contains(&info[j], info[i].tab);
if (super) {
int l;
unsigned total;
if (isl_tab_rollback(info[i].tab, snap2) < 0)
return isl_change_error;
info[i].bmap = isl_basic_map_cow(info[i].bmap);
if (!info[i].bmap)
return isl_change_error;
total = isl_basic_map_total_dim(info[i].bmap);
for (l = 0; l < info[i].bmap->n_div; ++l)
if (!isl_seq_eq(info[i].bmap->div[l],
info[j].bmap->div[l], 1 + 1 + total)) {
isl_int_set_si(info[i].bmap->div[l][0], 0);
info[i].simplify = 1;
}
isl_int_add_ui(info[i].bmap->ineq[k][0],
info[i].bmap->ineq[k][0], 1);
ISL_F_SET(info[i].bmap, ISL_BASIC_MAP_FINAL);
drop(&info[j]);
if (j < i)
exchange(&info[i], &info[j]);
change = isl_change_fuse;
} else
if (isl_tab_rollback(info[i].tab, snap) < 0)
return isl_change_error;
return change;
}
/* Data structure that keeps track of the wrapping constraints
* and of information to bound the coefficients of those constraints.
*
* bound is set if we want to apply a bound on the coefficients
* mat contains the wrapping constraints
* max is the bound on the coefficients (if bound is set)
*/
struct isl_wraps {
int bound;
isl_mat *mat;
isl_int max;
};
/* Update wraps->max to be greater than or equal to the coefficients
* in the equalities and inequalities of info->bmap that can be removed
* if we end up applying wrapping.
*/
static void wraps_update_max(struct isl_wraps *wraps,
struct isl_coalesce_info *info)
{
int k;
isl_int max_k;
unsigned total = isl_basic_map_total_dim(info->bmap);
isl_int_init(max_k);
for (k = 0; k < info->bmap->n_eq; ++k) {
if (info->eq[2 * k] == STATUS_VALID &&
info->eq[2 * k + 1] == STATUS_VALID)
continue;
isl_seq_abs_max(info->bmap->eq[k] + 1, total, &max_k);
if (isl_int_abs_gt(max_k, wraps->max))
isl_int_set(wraps->max, max_k);
}
for (k = 0; k < info->bmap->n_ineq; ++k) {
if (info->ineq[k] == STATUS_VALID ||
info->ineq[k] == STATUS_REDUNDANT)
continue;
isl_seq_abs_max(info->bmap->ineq[k] + 1, total, &max_k);
if (isl_int_abs_gt(max_k, wraps->max))
isl_int_set(wraps->max, max_k);
}
isl_int_clear(max_k);
}
/* Initialize the isl_wraps data structure.
* If we want to bound the coefficients of the wrapping constraints,
* we set wraps->max to the largest coefficient
* in the equalities and inequalities that can be removed if we end up
* applying wrapping.
*/
static void wraps_init(struct isl_wraps *wraps, __isl_take isl_mat *mat,
struct isl_coalesce_info *info, int i, int j)
{
isl_ctx *ctx;
wraps->bound = 0;
wraps->mat = mat;
if (!mat)
return;
ctx = isl_mat_get_ctx(mat);
wraps->bound = isl_options_get_coalesce_bounded_wrapping(ctx);
if (!wraps->bound)
return;
isl_int_init(wraps->max);
isl_int_set_si(wraps->max, 0);
wraps_update_max(wraps, &info[i]);
wraps_update_max(wraps, &info[j]);
}
/* Free the contents of the isl_wraps data structure.
*/
static void wraps_free(struct isl_wraps *wraps)
{
isl_mat_free(wraps->mat);
if (wraps->bound)
isl_int_clear(wraps->max);
}
/* Is the wrapping constraint in row "row" allowed?
*
* If wraps->bound is set, we check that none of the coefficients
* is greater than wraps->max.
*/
static int allow_wrap(struct isl_wraps *wraps, int row)
{
int i;
if (!wraps->bound)
return 1;
for (i = 1; i < wraps->mat->n_col; ++i)
if (isl_int_abs_gt(wraps->mat->row[row][i], wraps->max))
return 0;
return 1;
}
/* Wrap "ineq" (or its opposite if "negate" is set) around "bound"
* to include "set" and add the result in position "w" of "wraps".
* "len" is the total number of coefficients in "bound" and "ineq".
* Return 1 on success, 0 on failure and -1 on error.
* Wrapping can fail if the result of wrapping is equal to "bound"
* or if we want to bound the sizes of the coefficients and
* the wrapped constraint does not satisfy this bound.
*/
static int add_wrap(struct isl_wraps *wraps, int w, isl_int *bound,
isl_int *ineq, unsigned len, __isl_keep isl_set *set, int negate)
{
isl_seq_cpy(wraps->mat->row[w], bound, len);
if (negate) {
isl_seq_neg(wraps->mat->row[w + 1], ineq, len);
ineq = wraps->mat->row[w + 1];
}
if (!isl_set_wrap_facet(set, wraps->mat->row[w], ineq))
return -1;
if (isl_seq_eq(wraps->mat->row[w], bound, len))
return 0;
if (!allow_wrap(wraps, w))
return 0;
return 1;
}
/* For each constraint in info->bmap that is not redundant (as determined
* by info->tab) and that is not a valid constraint for the other basic map,
* wrap the constraint around "bound" such that it includes the whole
* set "set" and append the resulting constraint to "wraps".
* Note that the constraints that are valid for the other basic map
* will be added to the combined basic map by default, so there is
* no need to wrap them.
* The caller wrap_in_facets even relies on this function not wrapping
* any constraints that are already valid.
* "wraps" is assumed to have been pre-allocated to the appropriate size.
* wraps->n_row is the number of actual wrapped constraints that have
* been added.
* If any of the wrapping problems results in a constraint that is
* identical to "bound", then this means that "set" is unbounded in such
* way that no wrapping is possible. If this happens then wraps->n_row
* is reset to zero.
* Similarly, if we want to bound the coefficients of the wrapping
* constraints and a newly added wrapping constraint does not
* satisfy the bound, then wraps->n_row is also reset to zero.
*/
static int add_wraps(struct isl_wraps *wraps, struct isl_coalesce_info *info,
isl_int *bound, __isl_keep isl_set *set)
{
int l, m;
int w;
int added;
isl_basic_map *bmap = info->bmap;
unsigned len = 1 + isl_basic_map_total_dim(bmap);
w = wraps->mat->n_row;
for (l = 0; l < bmap->n_ineq; ++l) {
if (info->ineq[l] == STATUS_VALID ||
info->ineq[l] == STATUS_REDUNDANT)
continue;
if (isl_seq_is_neg(bound, bmap->ineq[l], len))
continue;
if (isl_seq_eq(bound, bmap->ineq[l], len))
continue;
if (isl_tab_is_redundant(info->tab, bmap->n_eq + l))
continue;
added = add_wrap(wraps, w, bound, bmap->ineq[l], len, set, 0);
if (added < 0)
return -1;
if (!added)
goto unbounded;
++w;
}
for (l = 0; l < bmap->n_eq; ++l) {
if (isl_seq_is_neg(bound, bmap->eq[l], len))
continue;
if (isl_seq_eq(bound, bmap->eq[l], len))
continue;
for (m = 0; m < 2; ++m) {
if (info->eq[2 * l + m] == STATUS_VALID)
continue;
added = add_wrap(wraps, w, bound, bmap->eq[l], len,
set, !m);
if (added < 0)
return -1;
if (!added)
goto unbounded;
++w;
}
}
wraps->mat->n_row = w;
return 0;
unbounded:
wraps->mat->n_row = 0;
return 0;
}
/* Check if the constraints in "wraps" from "first" until the last
* are all valid for the basic set represented by "tab".
* If not, wraps->n_row is set to zero.
*/
static int check_wraps(__isl_keep isl_mat *wraps, int first,
struct isl_tab *tab)
{
int i;
for (i = first; i < wraps->n_row; ++i) {
enum isl_ineq_type type;
type = isl_tab_ineq_type(tab, wraps->row[i]);
if (type == isl_ineq_error)
return -1;
if (type == isl_ineq_redundant)
continue;
wraps->n_row = 0;
return 0;
}
return 0;
}
/* Return a set that corresponds to the non-redundant constraints
* (as recorded in tab) of bmap.
*
* It's important to remove the redundant constraints as some
* of the other constraints may have been modified after the
* constraints were marked redundant.
* In particular, a constraint may have been relaxed.
* Redundant constraints are ignored when a constraint is relaxed
* and should therefore continue to be ignored ever after.
* Otherwise, the relaxation might be thwarted by some of
* these constraints.
*
* Update the underlying set to ensure that the dimension doesn't change.
* Otherwise the integer divisions could get dropped if the tab
* turns out to be empty.
*/
static __isl_give isl_set *set_from_updated_bmap(__isl_keep isl_basic_map *bmap,
struct isl_tab *tab)
{
isl_basic_set *bset;