isl_polynomial.c: sort_divs: fix ordering of div rows

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

diff --git a/isl_polynomial.c b/isl_polynomial.c
index e6becb2..1ef03da 100644 (file)
--- a/isl_polynomial.c
+++ b/isl_polynomial.c
@@ -1071,7 +1071,7 @@ static __isl_give isl_qpolynomial *sort_divs(__isl_take isl_qpolynomial *qp)
 {
        int i;
        struct isl_div_sort_info *array = NULL;
-       int *pos = NULL;
+       int *pos = NULL, *at = NULL;
        int *reordering = NULL;
        unsigned div_pos;
 
@@ -1085,14 +1085,16 @@ static __isl_give isl_qpolynomial *sort_divs(__isl_take isl_qpolynomial *qp)
        array = isl_alloc_array(qp->div->ctx, struct isl_div_sort_info,
                                qp->div->n_row);
        pos = isl_alloc_array(qp->div->ctx, int, qp->div->n_row);
+       at = isl_alloc_array(qp->div->ctx, int, qp->div->n_row);
        reordering = isl_alloc_array(qp->div->ctx, int, qp->div->n_col - 2);
-       if (!array || !pos || !reordering)
+       if (!array || !pos || !at || !reordering)
                goto error;
 
        for (i = 0; i < qp->div->n_row; ++i) {
                array[i].div = qp->div;
                array[i].row = i;
                pos[i] = i;
+               at[i] = i;
        }
 
        qsort(array, qp->div->n_row, sizeof(struct isl_div_sort_info),
@@ -1105,14 +1107,13 @@ static __isl_give isl_qpolynomial *sort_divs(__isl_take isl_qpolynomial *qp)
                reordering[div_pos + array[i].row] = div_pos + i;
 
        for (i = 0; i < qp->div->n_row; ++i) {
-               int t;
                if (pos[array[i].row] == i)
                        continue;
-               qp->div = isl_mat_cow(qp->div);
                qp->div = isl_mat_swap_rows(qp->div, i, pos[array[i].row]);
-               t = pos[array[i].row];
-               pos[array[i].row] = pos[i];
-               pos[i] = t;
+               pos[at[i]] = pos[array[i].row];
+               at[pos[array[i].row]] = at[i];
+               at[i] = array[i].row;
+               pos[array[i].row] = i;
        }
 
        qp->upoly = reorder(qp->upoly, reordering);
@@ -1120,12 +1121,14 @@ static __isl_give isl_qpolynomial *sort_divs(__isl_take isl_qpolynomial *qp)
        if (!qp->upoly || !qp->div)
                goto error;
 
+       free(at);
        free(pos);
        free(array);
        free(reordering);
 
        return qp;
 error:
+       free(at);
        free(pos);
        free(array);
        free(reordering);