[clang] [llvm] [RISCV] Add processor definition for SiFive P870 (PR #137725)

[Min-Yih Hsu via cfe-commits]

mshockwave wrote:

> LLVM Buildbot has detected a new failure on builder `arc-builder` running on `arc-worker` while building `clang,llvm` at step 6 "test-build-unified-tree-check-all".
> 
> Full details are available at: https://lab.llvm.org/buildbot/#/builders/3/builds/15497
> 
> Here is the relevant piece of the build log for the reference

I couldn't reproduce this failure and I'm a bit confused: it couldn't recognized `sifive-p870` as mcpu value in `clang/test/Driver/riscv-cpus.c` and `clang/test/Misc/target-invalid-cpu-note/riscv.c` -- but if it couldn't recognized this CPU name, shouldn't `clang/test/Driver/print-enabled-extensions/riscv-sifive-p870.c` also failed?
Plus, this patch passed on many other buildbots.

https://github.com/llvm/llvm-project/pull/137725