isl_basic_set_opt: avoid invalid access on error path

[platform/upstream/isl.git] / isl_local_space.c

diff --git a/isl_local_space.c b/isl_local_space.c
index bce4399..6c4fb84 100644 (file)
--- a/isl_local_space.c
+++ b/isl_local_space.c
@@ -752,7 +752,7 @@ error:
 
 /* Plug in the affine expressions "subs" of length "subs_len" (including
  * the denominator and the constant term) into the variable at position "pos"
- * of all the div expressions starting at "first".
+ * of the "n" div expressions starting at "first".
  *
  * Let i be the dimension to replace and let "subs" be of the form
  *
@@ -769,11 +769,13 @@ error:
 __isl_give isl_local_space *isl_local_space_substitute_seq(
        __isl_take isl_local_space *ls,
        enum isl_dim_type type, unsigned pos, isl_int *subs, int subs_len,
-       int first)
+       int first, int n)
 {
        int i;
        isl_int v;
 
+       if (n == 0)
+               return ls;
        ls = isl_local_space_cow(ls);
        if (!ls)
                return NULL;
@@ -781,6 +783,10 @@ __isl_give isl_local_space *isl_local_space_substitute_seq(
        if (!ls->div)
                return isl_local_space_free(ls);
 
+       if (first + n > ls->div->n_row)
+               isl_die(isl_local_space_get_ctx(ls), isl_error_invalid,
+                       "index out of bounds", return isl_local_space_free(ls));
+
        pos += isl_local_space_offset(ls, type);
 
        isl_int_init(v);
@@ -828,7 +834,7 @@ __isl_give isl_local_space *isl_local_space_substitute(
                        return isl_local_space_free(ls));
 
        return isl_local_space_substitute_seq(ls, type, pos, subs->v->el,
-                                               subs->v->size, 0);
+                                           subs->v->size, 0, ls->div->n_row);
 }
 
 int isl_local_space_is_named_or_nested(__isl_keep isl_local_space *ls,
@@ -1034,3 +1040,85 @@ __isl_give isl_basic_map *isl_local_space_lifting(
 
        return lifting;
 }
+
+/* Compute the preimage of "ls" under the function represented by "ma".
+ * In other words, plug in "ma" in "ls".  The result is a local space
+ * that is part of the domain space of "ma".
+ *
+ * If the divs in "ls" are represented as
+ *
+ *     floor((a_i(p) + b_i x + c_i(divs))/n_i)
+ *
+ * and ma is represented by
+ *
+ *     x = D(p) + F(y) + G(divs')
+ *
+ * then the resulting divs are
+ *
+ *     floor((a_i(p) + b_i D(p) + b_i F(y) + B_i G(divs') + c_i(divs))/n_i)
+ *
+ * We first copy over the divs from "ma" and then
+ * we add the modified divs from "ls".
+ */
+__isl_give isl_local_space *isl_local_space_preimage_multi_aff(
+       __isl_take isl_local_space *ls, __isl_take isl_multi_aff *ma)
+{
+       int i;
+       isl_space *space;
+       isl_local_space *res = NULL;
+       int n_div_ls, n_div_ma;
+       isl_int f, c1, c2, g;
+
+       ma = isl_multi_aff_align_divs(ma);
+       if (!ls || !ma)
+               goto error;
+       if (!isl_space_is_range_internal(ls->dim, ma->space))
+               isl_die(isl_local_space_get_ctx(ls), isl_error_invalid,
+                       "spaces don't match", goto error);
+
+       n_div_ls = isl_local_space_dim(ls, isl_dim_div);
+       n_div_ma = ma->n ? isl_aff_dim(ma->p[0], isl_dim_div) : 0;
+
+       space = isl_space_domain(isl_multi_aff_get_space(ma));
+       res = isl_local_space_alloc(space, n_div_ma + n_div_ls);
+       if (!res)
+               goto error;
+
+       if (n_div_ma) {
+               isl_mat_free(res->div);
+               res->div = isl_mat_copy(ma->p[0]->ls->div);
+               res->div = isl_mat_add_zero_cols(res->div, n_div_ls);
+               res->div = isl_mat_add_rows(res->div, n_div_ls);
+               if (!res->div)
+                       goto error;
+       }
+
+       isl_int_init(f);
+       isl_int_init(c1);
+       isl_int_init(c2);
+       isl_int_init(g);
+
+       for (i = 0; i < ls->div->n_row; ++i) {
+               if (isl_int_is_zero(ls->div->row[i][0])) {
+                       isl_int_set_si(res->div->row[n_div_ma + i][0], 0);
+                       continue;
+               }
+               isl_seq_preimage(res->div->row[n_div_ma + i], ls->div->row[i],
+                                   ma, n_div_ma, n_div_ls, f, c1, c2, g, 1);
+               normalize_div(res, n_div_ma + i);
+       }
+
+       isl_int_clear(f);
+       isl_int_clear(c1);
+       isl_int_clear(c2);
+       isl_int_clear(g);
+
+       isl_local_space_free(ls);
+       isl_multi_aff_free(ma);
+       return res;
+error:
+       isl_local_space_free(ls);
+       isl_multi_aff_free(ma);
+       isl_local_space_free(res);
+       return NULL;
+}