fix long standing bug in isl_mat_inverse_product

diff --git a/isl_mat.c b/isl_mat.c
index 1479993..3b92458 100644 (file)
--- a/isl_mat.c
+++ b/isl_mat.c
@@ -603,11 +603,11 @@ struct isl_mat *isl_mat_inverse_product(struct isl_mat *left,
                        isl_int_gcd(a, left->row[row][row], left->row[i][row]);
                        isl_int_divexact(b, left->row[i][row], a);
                        isl_int_divexact(a, left->row[row][row], a);
-                       isl_int_neg(a, a);
-                       isl_seq_combine(left->row[i]+row,
-                                       a, left->row[i]+row,
-                                       b, left->row[row]+row,
-                                       left->n_col-row);
+                       isl_int_neg(b, b);
+                       isl_seq_combine(left->row[i] + i,
+                                       a, left->row[i] + i,
+                                       b, left->row[row] + i,
+                                       left->n_col - i);
                        isl_seq_combine(right->row[i], a, right->row[i],
                                        b, right->row[row], right->n_col);
                }