add isl_basic_set_compare_at

diff --git a/include/isl_set.h b/include/isl_set.h
index 920640a..8d5dfaf 100644 (file)
--- a/include/isl_set.h
+++ b/include/isl_set.h
@@ -106,6 +106,9 @@ struct isl_set *isl_basic_set_union(
                struct isl_basic_set *bset1,
                struct isl_basic_set *bset2);
 
+int isl_basic_set_compare_at(struct isl_basic_set *bset1,
+       struct isl_basic_set *bset2, int pos);
+
 struct isl_set *isl_set_alloc(struct isl_ctx *ctx,
                unsigned nparam, unsigned dim, int n, unsigned flags);
 struct isl_set *isl_set_extend(struct isl_set *base,

diff --git a/isl_map.c b/isl_map.c
index c9eea41..9a135a9 100644 (file)
--- a/isl_map.c
+++ b/isl_map.c
@@ -2,6 +2,7 @@
 #include <strings.h>
 #include "isl_ctx.h"
 #include "isl_blk.h"
+#include "isl_lp.h"
 #include "isl_seq.h"
 #include "isl_set.h"
 #include "isl_map.h"
@@ -3600,3 +3601,73 @@ error:
        isl_basic_set_free(bset);
        return NULL;
 }
+
+/* Given two _disjoint_ basic sets bset1 and bset2, check whether
+ * for any common value of the parameters and dimensions preceding dim
+ * in both basic sets, the values of dimension pos in bset1 are
+ * smaller or larger then those in bset2.
+ *
+ * Returns
+ *      1 if bset1 follows bset2
+ *     -1 if bset1 precedes bset2
+ *      0 if bset1 and bset2 are incomparable
+ *     -2 if some error occurred.
+ */
+int isl_basic_set_compare_at(struct isl_basic_set *bset1,
+       struct isl_basic_set *bset2, int pos)
+{
+       struct isl_basic_map *bmap1 = NULL;
+       struct isl_basic_map *bmap2 = NULL;
+       struct isl_ctx *ctx;
+       struct isl_vec *obj;
+       unsigned total;
+       isl_int num, den;
+       enum isl_lp_result res;
+       int cmp;
+
+       if (!bset1 || !bset2)
+               return -2;
+
+       bmap1 = isl_basic_map_from_basic_set(isl_basic_set_copy(bset1),
+                                               pos, bset1->dim - pos);
+       bmap2 = isl_basic_map_from_basic_set(isl_basic_set_copy(bset2),
+                                               pos, bset2->dim - pos);
+       if (!bmap1 || !bmap2)
+               goto error;
+       bmap1 = isl_basic_map_extend(bmap1, bmap1->nparam,
+                       bmap1->n_in, bmap1->n_out + bmap2->n_out,
+                       bmap2->n_div, bmap2->n_eq, bmap2->n_ineq);
+       if (!bmap1)
+               goto error;
+       total = bmap1->nparam + bmap1->n_in + bmap1->n_out + bmap1->n_div;
+       ctx = bmap1->ctx;
+       obj = isl_vec_alloc(ctx, total);
+       isl_seq_clr(obj->block.data, total);
+       isl_int_set_si(obj->block.data[bmap1->nparam+bmap1->n_in], 1);
+       isl_int_set_si(obj->block.data[bmap1->nparam+bmap1->n_in+
+                                       bmap1->n_out-bmap2->n_out], -1);
+       if (!obj)
+               goto error;
+       bmap1 = add_constraints(bmap1, bmap2, 0, bmap1->n_out - bmap2->n_out);
+       isl_int_init(num);
+       isl_int_init(den);
+       res = isl_solve_lp(bmap1, 0, obj->block.data, ctx->one, &num, &den);
+       if (res == isl_lp_empty)
+               cmp = 0;
+       else if (res == isl_lp_ok && isl_int_is_pos(num))
+               cmp = 1;
+       else if ((res == isl_lp_ok && isl_int_is_neg(num)) ||
+                 res == isl_lp_unbounded)
+               cmp = -1;
+       else
+               cmp = -2;
+       isl_int_clear(num);
+       isl_int_clear(den);
+       isl_basic_map_free(bmap1);
+       isl_vec_free(ctx, obj);
+       return cmp;
+error:
+       isl_basic_map_free(bmap1);
+       isl_basic_map_free(bmap2);
+       return -2;
+}