Targets affected:
- NVPTX and BPF: set to 64 bits.
- ARC, Lanai, and MSP430: set to 0 (they don't implement atomics).
Those which didn't yet add AtomicExpandPass to their pass pipeline now
do so.
This will result in larger atomic operations getting expanded to
`__atomic_*` libcalls via AtomicExpandPass. On all these targets, this
now matches what Clang already does in the frontend.
The only targets which do not configure AtomicExpandPass now are:
- DirectX and SPIRV: they aren't normal backends.
- AVR: a single-cpu architecture with no privileged/user divide, which
could implement all atomics by disabling/enabling interrupts, regardless
of size/alignment. Will be addressed by future work.
This is a follow-up to b71edfaa4ec3c998aadb35255ce2f60bba2940b0
since I forgot the lit.local.cfg files in that one.
Reformatting is done with `black`.
If you end up having problems merging this commit because you
have made changes to a python file, the best way to handle that
is to run git checkout --ours <yourfile> and then reformat it
with black.
If you run into any problems, post to discourse about it and
we will try to help.
RFC Thread below:
https://discourse.llvm.org/t/rfc-document-and-standardize-python-code-style
Reviewed By: barannikov88, kwk
Differential Revision: https://reviews.llvm.org/D150762
