isl_set_lift: preserve structure of space

Before, we would simply add extra variables to the dimension specification,
if needed, destroying any internal structure.  Now, we retain the original
dimension specification as the domain of a wrapped map.

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

diff --git a/isl_dim.c b/isl_dim.c
index 16088f0..df4c1f8 100644 (file)
--- a/isl_dim.c
+++ b/isl_dim.c
@@ -1189,3 +1189,27 @@ error:
        isl_dim_free(dst);
        return NULL;
 }
+
+/* Given a dimension specification "dim" of a set, create a dimension
+ * specification for the lift of the set.  In particular, the result
+ * is of the form [dim -> local[..]], with n_local variables in the
+ * range of the wrapped map.
+ */
+__isl_give isl_dim *isl_dim_lift(__isl_take isl_dim *dim, unsigned n_local)
+{
+       isl_dim *local_dim;
+
+       if (!dim)
+               return NULL;
+
+       local_dim = isl_dim_dup(dim);
+       local_dim = isl_dim_drop(local_dim, isl_dim_set, 0, dim->n_out);
+       local_dim = isl_dim_add(local_dim, isl_dim_set, n_local);
+       local_dim = isl_dim_set_tuple_name(local_dim, isl_dim_set, "local");
+       dim = isl_dim_join(isl_dim_from_domain(dim),
+                           isl_dim_from_range(local_dim));
+       dim = isl_dim_wrap(dim);
+       dim = isl_dim_set_tuple_name(dim, isl_dim_set, "lifted");
+
+       return dim;
+}

diff --git a/isl_dim_private.h b/isl_dim_private.h
index 0b4931c..a8c6007 100644 (file)
--- a/isl_dim_private.h
+++ b/isl_dim_private.h
@@ -31,3 +31,5 @@ __isl_give isl_dim *isl_dim_flatten(__isl_take isl_dim *dim);
 
 __isl_give isl_dim *isl_dim_replace(__isl_take isl_dim *dst,
        enum isl_dim_type type, __isl_keep isl_dim *src);
+
+__isl_give isl_dim *isl_dim_lift(__isl_take isl_dim *dim, unsigned n_local);

diff --git a/isl_map.c b/isl_map.c
index 06aa85c..5d7cf9e 100644 (file)
--- a/isl_map.c
+++ b/isl_map.c
@@ -7390,15 +7390,12 @@ __isl_give isl_basic_set *isl_basic_set_lift(__isl_take isl_basic_set *bset)
        if (!bset)
                return NULL;
 
-       if (bset->n_div == 0)
-               return bset;
-
        bset = isl_basic_set_cow(bset);
        if (!bset)
                return NULL;
 
        dim = isl_basic_set_get_dim(bset);
-       dim = isl_dim_add(dim, isl_dim_set, bset->n_div);
+       dim = isl_dim_lift(dim, bset->n_div);
        if (!dim)
                goto error;
        isl_dim_free(bset->dim);
@@ -7424,8 +7421,6 @@ __isl_give isl_set *isl_set_lift(__isl_take isl_set *set)
 
        if (!set)
                return NULL;
-       if (set->n == 0 || set->p[0]->n_div == 0)
-               return set;
 
        set = isl_set_cow(set);
        if (!set)
@@ -7433,7 +7428,7 @@ __isl_give isl_set *isl_set_lift(__isl_take isl_set *set)
 
        n_div = set->p[0]->n_div;
        dim = isl_set_get_dim(set);
-       dim = isl_dim_add(dim, isl_dim_set, n_div);
+       dim = isl_dim_lift(dim, n_div);
        if (!dim)
                goto error;
        isl_dim_free(set->dim);