message: Add best cost in autotile cost model
diff: @@ -74,7 +74,7 @@ private:
  // ArrayRef<int64_t>) to a double, which is 'inf' for infeasible tilings. For
  // example:
  -inline double DummyCostModel(ArrayRef<int64_t> tile) { return 1.0; }
  +inline double DummyCostModel(ArrayRef<int64_t> tile, double bestCost) { return 1.0; }
  // Given a generator and cost model, find the best tile size, return empty
  // tiling when all tiles are infeasible
  @@ -96,7 +96,7 @@ llvm::SmallVector<int64_t, 8> findBestTileSize(const Generator &generator,
  // Build a recursive lambda to walk over the options (thanks c++14!)
  auto recurse = [&](auto &self, size_t idx) -> void {
  if (idx == allowedTileSizes.size()) {
  - double newCost = costModel(curTileSize);
  + double newCost = costModel(curTileSize, bestCost);
  if (newCost < bestCost) {
  bestCost = newCost;
  bestTileSize = curTileSize;
  