isl_tab_sample: treat emptiness of tableau as error

We only modify the tableau through calls to isl_tab_add_valid_eq,
which should never result in an empty tableau, given that
the tableau was initially not empty.

Signed-off-by: Sven Verdoolaege <skimo@kotnet.org>

diff --git a/isl_sample.c b/isl_sample.c
index 197f0b5..d9cdc00 100644 (file)
--- a/isl_sample.c
+++ b/isl_sample.c
@@ -455,16 +455,16 @@ struct isl_vec *isl_tab_sample(struct isl_tab *tab)
        reduced = 0;
 
        while (level >= 0) {
        reduced = 0;
 
        while (level >= 0) {

-               int empty = 0;

                if (init) {
                        res = isl_tab_min(tab, tab->basis->row[1 + level],
                                    ctx->one, &min->el[level], NULL, 0);
                if (init) {
                        res = isl_tab_min(tab, tab->basis->row[1 + level],
                                    ctx->one, &min->el[level], NULL, 0);

-                       if (res == isl_lp_empty)
-                               empty = 1;
-                       isl_assert(ctx, res != isl_lp_unbounded, goto error);

                        if (res == isl_lp_error)
                                goto error;
                        if (res == isl_lp_error)
                                goto error;

-                       if (!empty && isl_tab_sample_is_integer(tab))
+                       if (res != isl_lp_ok)
+                               isl_die(ctx, isl_error_internal,
+                                       "expecting bounded rational solution",
+                                       goto error);
+                       if (isl_tab_sample_is_integer(tab))

                                break;
                        isl_seq_neg(tab->basis->row[1 + level] + 1,
                                    tab->basis->row[1 + level] + 1, dim);
                                break;
                        isl_seq_neg(tab->basis->row[1 + level] + 1,
                                    tab->basis->row[1 + level] + 1, dim);


@@ -473,15 +473,15 @@ struct isl_vec *isl_tab_sample(struct isl_tab *tab)
                        isl_seq_neg(tab->basis->row[1 + level] + 1,
                                    tab->basis->row[1 + level] + 1, dim);
                        isl_int_neg(max->el[level], max->el[level]);
                        isl_seq_neg(tab->basis->row[1 + level] + 1,
                                    tab->basis->row[1 + level] + 1, dim);
                        isl_int_neg(max->el[level], max->el[level]);

-                       if (res == isl_lp_empty)
-                               empty = 1;
-                       isl_assert(ctx, res != isl_lp_unbounded, goto error);

                        if (res == isl_lp_error)
                                goto error;
                        if (res == isl_lp_error)
                                goto error;

-                       if (!empty && isl_tab_sample_is_integer(tab))
+                       if (res != isl_lp_ok)
+                               isl_die(ctx, isl_error_internal,
+                                       "expecting bounded rational solution",
+                                       goto error);
+                       if (isl_tab_sample_is_integer(tab))

                                break;
                                break;

-                       if (!empty && !reduced &&
-                           ctx->opt->gbr != ISL_GBR_NEVER &&
+                       if (!reduced && ctx->opt->gbr != ISL_GBR_NEVER &&

                            isl_int_lt(min->el[level], max->el[level])) {
                                unsigned gbr_only_first;
                                if (ctx->opt->gbr == ISL_GBR_ONCE)
                            isl_int_lt(min->el[level], max->el[level])) {
                                unsigned gbr_only_first;
                                if (ctx->opt->gbr == ISL_GBR_ONCE)


@@ -502,7 +502,7 @@ struct isl_vec *isl_tab_sample(struct isl_tab *tab)
                } else
                        isl_int_add_ui(min->el[level], min->el[level], 1);
 
                } else
                        isl_int_add_ui(min->el[level], min->el[level], 1);
 

-               if (empty || isl_int_gt(min->el[level], max->el[level])) {
+               if (isl_int_gt(min->el[level], max->el[level])) {

                        level--;
                        init = 0;
                        if (level >= 0)
                        level--;
                        init = 0;
                        if (level >= 0)