isl_basic_set_sample: break early if sample found in basic_set_range

diff --git a/isl_sample.c b/isl_sample.c
index 5f5ff94..37045f9 100644 (file)
--- a/isl_sample.c
+++ b/isl_sample.c
@@ -179,6 +179,9 @@ static struct isl_vec *sample_eq(struct isl_basic_set *bset,
  * The minimal value is rounded up to the nearest integer, while the
  * maximal value is rounded down.
  * The return value indicates whether the set was empty or unbounded.
+ *
+ * If we happen to find an integer point while looking for the minimal
+ * or maximal value, then we record that value in "bset" and return early.
  */
 static enum isl_lp_result basic_set_range(struct isl_basic_set *bset,
        isl_int *f, isl_int denom, isl_int *min, isl_int *max)
@@ -194,18 +197,37 @@ static enum isl_lp_result basic_set_range(struct isl_basic_set *bset,
 
        tab = isl_tab_from_basic_set(bset);
        res = isl_tab_min(bset->ctx, tab, f, denom, min, NULL, 0);
-       if (res != isl_lp_ok) {
-               isl_tab_free(bset->ctx, tab);
-               return res;
+       if (res != isl_lp_ok)
+               goto done;
+
+       if (isl_tab_sample_is_integer(bset->ctx, tab)) {
+               isl_vec_free(bset->sample);
+               bset->sample = isl_tab_get_sample_value(bset->ctx, tab);
+               if (!bset->sample)
+                       goto error;
+               isl_int_set(*max, *min);
+               goto done;
        }
+
        dim = isl_basic_set_total_dim(bset);
        isl_seq_neg(f, f, 1 + dim);
        res = isl_tab_min(bset->ctx, tab, f, denom, max, NULL, 0);
        isl_seq_neg(f, f, 1 + dim);
        isl_int_neg(*max, *max);
 
+       if (isl_tab_sample_is_integer(bset->ctx, tab)) {
+               isl_vec_free(bset->sample);
+               bset->sample = isl_tab_get_sample_value(bset->ctx, tab);
+               if (!bset->sample)
+                       goto error;
+       }
+
+done:
        isl_tab_free(bset->ctx, tab);
        return res;
+error:
+       isl_tab_free(bset->ctx, tab);
+       return isl_lp_error;
 }
 
 /* Perform a basis reduction on "bset" and return the inverse of
@@ -349,6 +371,11 @@ static struct isl_vec *sample_bounded(struct isl_basic_set *bset)
        if (res == isl_lp_error)
                goto error;
        isl_assert(bset->ctx, res != isl_lp_unbounded, goto error);
+       if (bset->sample) {
+               sample = isl_vec_copy(bset->sample);
+               isl_basic_set_free(bset);
+               goto out;
+       }
        if (res == isl_lp_empty || isl_int_lt(max, min)) {
                sample = empty_sample(bset);
                goto out;
@@ -363,6 +390,11 @@ static struct isl_vec *sample_bounded(struct isl_basic_set *bset)
                if (res == isl_lp_error)
                        goto error;
                isl_assert(bset->ctx, res != isl_lp_unbounded, goto error);
+               if (bset->sample) {
+                       sample = isl_vec_copy(bset->sample);
+                       isl_basic_set_free(bset);
+                       goto out;
+               }
                if (res == isl_lp_empty || isl_int_lt(max, min)) {
                        sample = empty_sample(bset);
                        goto out;