drop mergeConsecutiveMappingFilters

This function does not appear to have ever been used
outside PolyhedralMapperTest.FilterMerge.
Since only a single mapping filter gets created now,
the function should never be needed either.

Author: Sven Verdoolaege

tc/core/polyhedral/schedule_transforms.cc

@@ -754,52 +754,5 @@ void orderAfter(ScheduleTree* root, ScheduleTree* tree, isl::union_set filter) {
   parent->insertChild(childPos, std::move(seq));
 }
 
-detail::ScheduleTree* mergeConsecutiveMappingFilters(
-    detail::ScheduleTree* root,
-    detail::ScheduleTree* node) {
-  CHECK(
-      root->elemAs<ScheduleTreeElemDomain>() ||
-      root->elemAs<ScheduleTreeElemExtension>());
-  bool changed = true;
-  while (changed) {
-    changed = false;
-    auto filterNodes = detail::ScheduleTree::collect(
-        node, detail::ScheduleTreeType::MappingFilter);
-
-    for (auto f : filterNodes) {
-      auto p = f->ancestor(root, 1);
-      auto parentFilter = p->elemAs<ScheduleTreeElemMappingFilter>();
-      if (!parentFilter) {
-        continue;
-      }
-      auto filter = f->elemAs<ScheduleTreeElemMappingFilter>();
-      auto merged = parentFilter->filter_ & filter->filter_;
-      // We can only merge filters that have the same number of tuples
-      if (merged.n_set() != parentFilter->filter_.n_set() ||
-          merged.n_set() != filter->filter_.n_set()) {
-        continue;
-      }
-      p->elemAs<ScheduleTreeElemMappingFilter>()->filter_ = merged;
-      // const cast to replace in place rather than construct a new
-      // ScheduleTree object (which would not be more functional-style anyway)
-      auto& ids = const_cast<std::unordered_set<
-          mapping::MappingId,
-          typename mapping::MappingId::Hash>&>(
-          p->elemAs<ScheduleTreeElemMappingFilter>()->mappingIds);
-      for (auto id : filter->mappingIds) {
-        CHECK_EQ(0u, ids.count(id))
-            << "Error when merging filters\n"
-            << *f << "\nand\n"
-            << *p << "\nid: " << id << " mapped in both!";
-        ids.insert(id);
-      }
-      p->replaceChild(f->positionInParent(p), f->detachChild(0));
-      changed = true;
-      break;
-    }
-  }
-  return node;
-}
-
 } // namespace polyhedral
 } // namespace tc

tc/core/polyhedral/schedule_transforms.h

@@ -297,15 +297,6 @@ isl::union_set activeDomainPointsBelow(
     const detail::ScheduleTree* root,
     const detail::ScheduleTree* node);
 
-////////////////////////////////////////////////////////////////////////////////
-// Experimental
-////////////////////////////////////////////////////////////////////////////////
-// Mapping filters are introduced one mapping dimension at a time.
-// This merges consecutive filters.
-detail::ScheduleTree* mergeConsecutiveMappingFilters(
-    detail::ScheduleTree* root,
-    detail::ScheduleTree* node);
-
 } // namespace polyhedral
 } // namespace tc
 

test/test_cuda_mapper.cc

@@ -337,22 +337,6 @@ TEST_F(PolyhedralMapperTest, MergedContexts) {
   ASSERT_TRUE(std::string::npos != res.find(kExpectedMatmul_64_64_64)) << res;
 }
 
-TEST_F(PolyhedralMapperTest, FilterMerge) {
-  auto scop = PrepareAndJoinBands(makeMatmulTc());
-  auto schedule = scop->scheduleRoot();
-
-  // Unit test claims to use scop->globalParameterContext properly
-  auto context = scop->makeContext<int>({{"M", 64}, {"N", 64}, {"K", 64}});
-  auto& globalParameterContext =
-      const_cast<isl::set&>(scop->globalParameterContext);
-  globalParameterContext = globalParameterContext.intersect(context);
-  scop->domain() = scop->domain().intersect(globalParameterContext);
-
-  auto mscop = TileAndMapThreads(std::move(scop), {16, 16}, {32ul, 8ul});
-  mergeConsecutiveMappingFilters(schedule, schedule->child({0}));
-  mscop->codegen(specializedName);
-}
-
 TEST_F(PolyhedralMapperTest, Match1) {
   auto scop = PrepareAndJoinBands(makeMatmulTc());
   auto schedule = scop->scheduleRoot();