[llvm] [RISCV] Make Zcmt imply Zicsr. (PR #75464)

[Yvan Roux via llvm-commits]

yroux wrote:

I'm not really familiar with Zicsr either, but yes it is written in the Zcmt JVT CSR description that:

 `If Zcmt is implemented then JVT must also be implemented, but can contain a read-only value.`

which implies that Zicsr is required.  The full discussion on the relationship between Zcmt and Zicsr is available in this issue:

https://github.com/riscv/riscv-code-size-reduction/issues/179

https://github.com/llvm/llvm-project/pull/75464