extractDomainToIds: do not assume all mapping nodes contain the given ids

A subtree may have mapping filter nodes with different ids.  If this
function is called on such subtree, it would fail even if all branches
of a subtree are mapped to the given ids because it sees a mapping
filter node with different ids.  Simply ignore the node that does not
contain all of the requested ids.

The check was originally introduced in extractDomainToThreads and was
meant to ensure that all branches in the subtree are indeed mapped to
threads.  Instead, perform a stricter check inside extractDomainToIds
that all active domain elements were indeed mapped to the given
identifiers.

Author: ftynse

tc/core/polyhedral/cuda/mapped_scop.cc

@@ -509,7 +509,7 @@ isl::multi_union_pw_aff MappedScop::threadMappingSchedule(
     ids.emplace_back(mapping::ThreadId::makeId(i));
   }
   auto tupleId = isl::id(tree->ctx_, kBlock);
-  return extractDomainToIds(tree, ids, tupleId);
+  return extractDomainToIds(scop_->scheduleRoot(), tree, ids, tupleId);
 }
 
 isl::multi_union_pw_aff MappedScop::blockMappingSchedule(

tc/core/polyhedral/schedule_transforms.cc

@@ -806,6 +806,7 @@ void orderAfter(ScheduleTree* root, ScheduleTree* tree, isl::union_set filter) {
  * The result lives in a space of the form "tupleId"["ids"...].
  */
 isl::multi_union_pw_aff extractDomainToIds(
+    const detail::ScheduleTree* root,
     const detail::ScheduleTree* tree,
     const std::vector<mapping::MappingId>& ids,
     isl::id tupleId) {
@@ -821,14 +822,24 @@ isl::multi_union_pw_aff extractDomainToIds(
     auto mappingNode = mapping->elemAs<ScheduleTreeElemMappingFilter>();
     auto list = isl::union_pw_aff_list(tree->ctx_, ids.size());
     for (auto id : ids) {
-      CHECK_GT(mappingNode->mapping.count(id), 0) << "no mapping to id " << id;
+      if (mappingNode->mapping.count(id) == 0) {
+        break;
+      }
       auto idMap = mappingNode->mapping.at(id);
       list = list.add(idMap);
     }
+    // Ignore this node if it does not map to all required ids.
+    if (static_cast<size_t>(list.n()) != ids.size()) {
+      continue;
+    }
     auto nodeToIds = isl::multi_union_pw_aff(space, list);
     domainToIds = domainToIds.union_add(nodeToIds);
   }
 
+  TC_CHECK(activeDomainPoints(root, tree).is_subset(domainToIds.domain()))
+      << "not all domain points of" << activeDomainPoints(root, tree)
+      << "were mapped to the required ids";
+
   return domainToIds;
 }
 

tc/core/polyhedral/schedule_transforms.h

@@ -326,11 +326,12 @@ isl::union_set activeDomainPointsBelow(
     const detail::ScheduleTree* root,
     const detail::ScheduleTree* node);
 
-// Extract a mapping from the domain elements active at "tree"
-// to identifiers "ids", where all branches in "tree"
-// are assumed to have been mapped to these identifiers.
-// The result lives in a space of the form "tupleId"["ids"...].
+// Extract a mapping from the domain elements active at "tree" (in a tree
+// rooted at "root") to identifiers "ids", where all branches in "tree" are
+// assumed to have been mapped to these identifiers.  The result lives in a
+// space of the form "tupleId"["ids"...].
 isl::multi_union_pw_aff extractDomainToIds(
+    const detail::ScheduleTree* root,
     const detail::ScheduleTree* tree,
     const std::vector<mapping::MappingId>& ids,
     isl::id tupleId);