decouple isl_aff_substitute_equalities

isl_aff_substitute_equalities was being called from within two contexts:
isl_pw_aff_intersect_domain and isl_aff_gist.
In the first case, the space of the equalities was that of the space
of the isl_pw_aff, while in the second case, the space of the equalities
was a lifted copy of the _local_ space of the isl_aff.
The actual implementation of isl_aff_substitute_equalities assumed
the second case.

Split isl_aff_substitute_equalities into two functions, one for each
of these two cases.

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

diff --git a/isl_aff.c b/isl_aff.c
index f4f1976..5e5ea3d 100644 (file)
--- a/isl_aff.c
+++ b/isl_aff.c
@@ -723,7 +723,7 @@ __isl_give isl_aff *isl_aff_set_dim_name(__isl_take isl_aff *aff,
  * The integer divisions in this local space are assumed to appear
  * as regular dimensions in "eq".
  */
-static __isl_give isl_aff *isl_aff_substitute_equalities(
+static __isl_give isl_aff *isl_aff_substitute_equalities_lifted(
        __isl_take isl_aff *aff, __isl_take isl_basic_set *eq)
 {
        int i, j;
@@ -765,6 +765,26 @@ error:
        return NULL;
 }
 
+/* Exploit the equalities in "eq" to simplify the affine expression
+ * and the expressions of the integer divisions in the local space.
+ */
+static __isl_give isl_aff *isl_aff_substitute_equalities(
+       __isl_take isl_aff *aff, __isl_take isl_basic_set *eq)
+{
+       int n_div;
+
+       if (!aff || !eq)
+               goto error;
+       n_div = isl_local_space_dim(aff->ls, isl_dim_div);
+       if (n_div > 0)
+               eq = isl_basic_set_add(eq, isl_dim_set, n_div);
+       return isl_aff_substitute_equalities_lifted(aff, eq);
+error:
+       isl_basic_set_free(eq);
+       isl_aff_free(aff);
+       return NULL;
+}
+
 /* Look for equalities among the variables shared by context and aff
  * and the integer divisions of aff, if any.
  * The equalities are then used to eliminate coefficients and/or integer
@@ -791,7 +811,7 @@ __isl_give isl_aff *isl_aff_gist(__isl_take isl_aff *aff,
        }
 
        hull = isl_set_affine_hull(context);
-       return isl_aff_substitute_equalities(aff, hull);
+       return isl_aff_substitute_equalities_lifted(aff, hull);
 error:
        isl_aff_free(aff);
        isl_set_free(context);