[WS][NFC] Remove dead code, PartitionGraph (#8077)

Doesn't seem to be used anywhere

Author: masahi

lib/Dialect/TritonGPU/Transforms/WarpSpecialization/Partition.cpp

@@ -8,76 +8,6 @@ using namespace mlir;
 using namespace triton;
 using namespace triton::gpu;
 
-//===----------------------------------------------------------------------===//
-// PartitionGraph
-//===----------------------------------------------------------------------===//
-
-namespace {
-// A temporary node structure that can be used to build a graph of partitions.
-// The consumers have to be precomputed in order for the SCC iterator to have an
-// acceptable runtime complexity. This assumes the underlying loop is immutable.
-struct PartitionNode {
-  PartitionNode(const Partition *partition) : partition(partition) {}
-
-  // The partition this node represents.
-  const Partition *partition;
-  // Partitions that consume the outputs of this partition.
-  SmallVector<std::pair<const PartitionNode *, OpOperand *>> consumers;
-};
-
-// A graph of partitions that can be used to check for cycles and other schedule
-// invariants.
-struct PartitionGraph {
-  PartitionGraph(scf::ForOp loop, const WarpSchedule &schedule);
-
-  PartitionNode root;
-  llvm::MapVector<const Partition *, PartitionNode> nodes;
-};
-} // namespace
-
-PartitionGraph::PartitionGraph(scf::ForOp loop, const WarpSchedule &schedule)
-    : root(schedule.getRootPartition()) {
-  // Create the nodes at once. Afterwards, the map won't re-allocate and the
-  // pointers will be stable.
-  for (Partition &partition : schedule.getPartitions())
-    nodes.try_emplace(&partition, &partition);
-
-  // Wire up the graph. Consider the root node to be consumed by all other
-  // partitions so that it can be used as a virtual root.
-  for (PartitionNode &node : llvm::make_second_range(nodes))
-    root.consumers.emplace_back(&node, nullptr);
-
-  // Check the users of the partition outputs to wire the rest of the graph.
-  for (auto &[partition, node] : nodes) {
-    auto callback = [&, node = &node](Operation *owner, OpOperand &use) {
-      // Ignore uses in subsequent iterations.
-      if (isa<scf::YieldOp>(owner))
-        return;
-      PartitionNode &consumer =
-          nodes.find(schedule.getPartition(owner))->second;
-      node->consumers.emplace_back(&consumer, &use);
-    };
-    schedule.iterateOutputs(loop, partition, callback);
-  }
-}
-
-namespace llvm {
-template <> struct GraphTraits<PartitionGraph> {
-  using NodeRef = std::pair<const PartitionNode *, mlir::OpOperand *>;
-  static NodeRef getEntryNode(const PartitionGraph &graph) {
-    return {&graph.root, nullptr};
-  }
-
-  using ChildIteratorType = SmallVector<NodeRef>::const_iterator;
-  static ChildIteratorType child_begin(NodeRef node) {
-    return node.first->consumers.begin();
-  }
-  static ChildIteratorType child_end(NodeRef node) {
-    return node.first->consumers.end();
-  }
-};
-} // namespace llvm
-
 //===----------------------------------------------------------------------===//
 // WarpSchedule
 //===----------------------------------------------------------------------===//