Always use cuda.h to detect CUDA version. It's a more universal approach
compared to version.txt which is no longer present in recent CUDA versions.
Split the 'unknown CUDA version' warning in two:
* when detected CUDA version is partially supported by clang. It's expected to
work in general, at the feature parity with the latest supported CUDA
version. and may be missing support for the new features/instructions/GPU
variants. Clang will issue a warning.
* when detected version is new. Recent CUDA versions have been working with
clang reasonably well, and will likely to work similarly to the partially
supported ones above. Or it may not work at all. Clang will issue a warning and
proceed as if the latest known CUDA version was detected.
Differential Revision: https://reviews.llvm.org/D108247
This makes clang somewhat forward-compatible with new CUDA releases
without having to patch it for every minor release without adding
any new function.
If an unknown version is found, clang issues a warning (can be disabled
with -Wno-cuda-unknown-version) and assumes that it has detected
the latest known version. CUDA releases are usually supersets
of older ones feature-wise, so it should be sufficient to keep
released clang versions working with minor CUDA updates without
having to upgrade clang, too.
Differential Revision: https://reviews.llvm.org/D73231
Artem Belevich