[clang] [llvm] [RISCV] SiFive CLIC Support (PR #132481)

[Sam Elliott via llvm-commits]

lenary wrote:

For Info, the last time this was proposed was in 2020: https://reviews.llvm.org/D79521 - at that time, no vendor extensions had been accepted upstream, and there was not yet a policy for upstream supporting vendor extensions.

https://github.com/llvm/llvm-project/pull/132481