isl_tab_pip.c: add some debugging code

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

diff --git a/isl_tab_pip.c b/isl_tab_pip.c
index 110a523..f6e238a 100644 (file)
--- a/isl_tab_pip.c
+++ b/isl_tab_pip.c
@@ -1113,6 +1113,42 @@ static int first_neg(struct isl_tab *tab)
        return -1;
 }
 
+/* Check whether the invariant that all columns are lexico-positive
+ * is satisfied.  This function is not called from the current code
+ * but is useful during debugging.
+ */
+static void check_lexpos(struct isl_tab *tab)
+{
+       unsigned off = 2 + tab->M;
+       int col;
+       int var;
+       int row;
+
+       for (col = tab->n_dead; col < tab->n_col; ++col) {
+               if (tab->col_var[col] >= 0 &&
+                   (tab->col_var[col] < tab->n_param ||
+                    tab->col_var[col] >= tab->n_var - tab->n_div))
+                       continue;
+               for (var = tab->n_param; var < tab->n_var - tab->n_div; ++var) {
+                       if (!tab->var[var].is_row) {
+                               if (tab->var[var].index == col)
+                                       break;
+                               else
+                                       continue;
+                       }
+                       row = tab->var[var].index;
+                       if (isl_int_is_zero(tab->mat->row[row][off + col]))
+                               continue;
+                       if (isl_int_is_pos(tab->mat->row[row][off + col]))
+                               break;
+                       fprintf(stderr, "lexneg column %d (row %d)\n",
+                               col, row);
+               }
+               if (var >= tab->n_var - tab->n_div)
+                       fprintf(stderr, "zero column %d\n", col);
+       }
+}
+
 /* Resolve all known or obviously violated constraints through pivoting.
  * In particular, as long as we can find any violated constraint, we
  * look for a pivoting column that would result in the lexicographically