memory_promotion.cc: extract out shared add_range

This function isolates lower-level space manipulations and
uses the newly introduced isl::space::unnamed_set_from_params.
It may be useful to add a function similar to add_range to isl
itself, but for now it is easier to add the function locally.

Author: Sven Verdoolaege

tc/core/polyhedral/memory_promotion.cc

@@ -98,6 +98,14 @@ ScopedFootprint outputRanges(isl::map access) {
   }
   return footprint;
 }
+
+// Given a set space, construct a map space with the input as domain and
+// a range of the given size.
+isl::space add_range(isl::space space, unsigned dim) {
+  auto range = space.params().unnamed_set_from_params(dim);
+  return space.map_from_domain_and_range(range);
+}
+
 } // namespace
 
 // Access has the shape :: [D -> ref] -> O
@@ -128,8 +136,7 @@ std::unique_ptr<TensorReferenceGroup> TensorReferenceGroup::makeSingleton(
 }
 
 isl::set ScopedFootprint::footprint(isl::set domain) const {
-  auto space = domain.get_space().from_domain();
-  space = space.add_dims(isl::dim_type::out, size());
+  auto space = add_range(domain.get_space(), size());
   auto accessed = isl::map::universe(space).intersect_domain(domain);
   auto lspace = isl::local_space(accessed.get_space().range());
 
@@ -147,8 +154,7 @@ isl::multi_aff ScopedFootprint::lowerBounds() const {
   if (size() == 0) {
     throw promotion::PromotionNYI("promotion for scalars");
   }
-  auto space = at(0).lowerBound.get_space();
-  space = space.add_dims(isl::dim_type::out, size() - 1);
+  auto space = add_range(at(0).lowerBound.get_space().domain(), size());
   auto ma = isl::multi_aff::zero(space);
 
   int i = 0;
@@ -442,7 +448,7 @@ isl::multi_aff dropDummyTensorDimensions(
     }
   }
 
-  space = space.from_domain().add_dims(isl::dim_type::out, list.n());
+  space = add_range(space, list.n());
   return isl::multi_aff(space, list);
 }
 } // namespace