Build error with Clang

[roastduck]

torch-blocksparse/csrc/utils.cpp

Line 115 in 9aa9478

torch::Tensor scratch = torch::empty({H, layout.sum().item<int>(), 4}, layout.dtype());

Please have a look at this line. Implicit conversion from size_t to long is treated as an error in Clang.

  /tmp/pip-install-62i124mf/torch-blocksparse/csrc/utils.cpp:115:41: error: non-constant-expression cannot be narrowed from type 'size_
t' (aka 'unsigned long') to 'long' in initializer list [-Wc++11-narrowing]
    torch::Tensor scratch = torch::empty({H, layout.sum().item<int>(), 4}, layout.dtype());
                                          ^
  /tmp/pip-install-62i124mf/torch-blocksparse/csrc/utils.cpp:115:41: note: insert an explicit cast to silence this issue
    torch::Tensor scratch = torch::empty({H, layout.sum().item<int>(), 4}, layout.dtype());
                                          ^
                                          static_cast<long>( )

Using GCC avoids the error.