[clang] [llvm] [RISCV] Add SpacemiT XSMTVDot (SpacemiT Vector Dot Product) extension. (PR #151706)

[Jim Lin via llvm-commits]

================

----------------
tclin914 wrote:

Most vendor MC tests, including those for vector, are placed under `llvm/test/MC/RISCV`, except for SiFive’s.

https://github.com/llvm/llvm-project/pull/151706