Summary:
- The device compilation needs to have a consistent source code compared
to the corresponding host compilation. If macros based on the
host-specific target processor is not properly populated, the device
compilation may fail due to the inconsistent source after the
preprocessor. So far, only the host triple is used to build the
macros. If a detailed host CPU target or certain features are
specified, macros derived from them won't be populated properly, e.g.
`__SSE3__` won't be added unless `+sse3` feature is present. On
Windows compilation compatible with MSVC, that missing macros result
in that intrinsics are not included and cause device compilation
failure on the host-side source.
- This patch addresses this issue by introducing two `cc1` options,
i.e., `-aux-target-cpu` and `-aux-target-feature`. If a specific host
CPU target or certain features are specified, the compiler driver will
append them during the construction of the offline compilation
actions. Then, the toolchain in `cc1` phase will populate macros
accordingly.
- An internal option `--gpu-use-aux-triple-only` is added to fall back
the original behavior to help diagnosing potential issues from the new
behavior.
Reviewers: tra, yaxunl
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D73942
Yaxun (Sam) Liu