message: add memory barrier for safety
diff: @@ -968,6 +968,8 @@ __global__ __launch_bounds__(default_block_size) void build_csr_lookup(
  for (int32 i = lane; i < num_blocks; i += subwarp_size) {
  block_bitmaps[i] = 0;
  }
  + // memory barrier - just to be sure
  + subwarp.sync();
  // fill bitmaps with sparsity pattern
  for (IndexType base_i = 0; base_i < row_len; base_i += subwarp_size) {
  const auto i = base_i + lane;
  