IterationDomain: also keep track of original parameter space

The function makeIslAffBoundsFromExpr will be changed
to only take a parameter space as input.
Scop::makeIslAffFromStmtExpr therefore needs to have access
to the set of all parameters available at the point where
the iteration domain is constructed.
Store them in IterationDomain for reuse
in Scop::makeIslAffFromStmtExpr.
Note that these parameters are not available as such
in the iteration domain tuple since they are not parameters
from the point of view of the iteration domain.

Author: Sven Verdoolaege

tc/core/halide2isl.cc

@@ -433,6 +433,7 @@ isl::schedule makeScheduleTreeHelper(
     auto tupleSpace = isl::space(set.get_ctx(), 0);
     tupleSpace = tupleSpace.named_set_from_params_id(id, outer.n());
     IterationDomain iterationDomain;
+    iterationDomain.paramSpace = set.get_space();
     iterationDomain.tuple = isl::multi_id(tupleSpace, outer);
     domains->emplace(id, iterationDomain);
     auto domain = set.unbind_params(iterationDomain.tuple);

tc/core/halide2isl.h

@@ -58,6 +58,9 @@ isl::aff makeIslAffFromExpr(isl::space space, const Halide::Expr& e);
 
 // Iteration domain information associated to a statement identifier.
 struct IterationDomain {
+  // All parameters active at the point where the iteration domain
+  // was created, including those corresponding to outer loop iterators.
+  isl::space paramSpace;
   // The identifier tuple corresponding to the iteration domain.
   // The identifiers in the tuple are the outer loop iterators,
   // from outermost to innermost.