isl_pw_aff_non_zero_set: don't assume isl_pw_aff is total

Before, we would return the domain where the function is not zero
or undefined, whereas we should only return the domain where the function
is not zero.

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

diff --git a/isl_aff.c b/isl_aff.c
index 42000ce..ca86174 100644 (file)
--- a/isl_aff.c
+++ b/isl_aff.c
@@ -1478,9 +1478,11 @@ __isl_give isl_set *isl_pw_aff_nonneg_set(__isl_take isl_pw_aff *pwaff)
 }
 
 /* Return a set containing those elements in the domain
- * of pwaff where it is zero.
+ * of pwaff where it is zero (if complement is 0) or not zero
+ * (if complement is 1).
  */
-__isl_give isl_set *isl_pw_aff_zero_set(__isl_take isl_pw_aff *pwaff)
+static __isl_give isl_set *pw_aff_zero_set(__isl_take isl_pw_aff *pwaff,
+       int complement)
 {
        int i;
        isl_set *set;
@@ -1492,11 +1494,15 @@ __isl_give isl_set *isl_pw_aff_zero_set(__isl_take isl_pw_aff *pwaff)
 
        for (i = 0; i < pwaff->n; ++i) {
                isl_basic_set *bset;
-               isl_set *set_i;
+               isl_set *set_i, *zero;
 
                bset = isl_aff_zero_basic_set(isl_aff_copy(pwaff->p[i].aff));
-               set_i = isl_set_from_basic_set(bset);
-               set_i = isl_set_intersect(set_i, isl_set_copy(pwaff->p[i].set));
+               zero = isl_set_from_basic_set(bset);
+               set_i = isl_set_copy(pwaff->p[i].set);
+               if (complement)
+                       set_i = isl_set_subtract(set_i, zero);
+               else
+                       set_i = isl_set_intersect(set_i, zero);
                set = isl_set_union_disjoint(set, set_i);
        }
 
@@ -1506,11 +1512,19 @@ __isl_give isl_set *isl_pw_aff_zero_set(__isl_take isl_pw_aff *pwaff)
 }
 
 /* Return a set containing those elements in the domain
+ * of pwaff where it is zero.
+ */
+__isl_give isl_set *isl_pw_aff_zero_set(__isl_take isl_pw_aff *pwaff)
+{
+       return pw_aff_zero_set(pwaff, 0);
+}
+
+/* Return a set containing those elements in the domain
  * of pwaff where it is not zero.
  */
 __isl_give isl_set *isl_pw_aff_non_zero_set(__isl_take isl_pw_aff *pwaff)
 {
-       return isl_set_complement(isl_pw_aff_zero_set(pwaff));
+       return pw_aff_zero_set(pwaff, 1);
 }
 
 /* Return a set containing those elements in the shared domain