message: fix overflow in thread index calculation
diff: @@ -501,7 +501,7 @@ __global__ __launch_bounds__(default_block_size) void spgeam_nnz(
  IndexType num_rows, IndexType *nnz)
  {
  constexpr auto sentinel = device_numeric_limits<IndexType>::max;
  - auto row = threadIdx.x + blockDim.x * blockIdx.x;
  + auto row = threadIdx.x + blockDim.x * static_cast<size_type>(blockIdx.x);
  if (row >= num_rows) {
  return;
  }
  @@ -544,7 +544,7 @@ __global__ __launch_bounds__(default_block_size) void spgeam(
  const IndexType *c_row_ptrs, IndexType *c_col_idxs, ValueType *c_vals)
  {
  constexpr auto sentinel = device_numeric_limits<IndexType>::max;
  - auto row = threadIdx.x + blockDim.x * blockIdx.x;
  + auto row = threadIdx.x + blockDim.x * static_cast<size_type>(blockIdx.x);
  if (row >= num_rows) {
  return;
  }
  