[llvm] [RISCV][TableGen] Generate RISCVTargetParser.inc from the new RISCVExtension tblgen information. (PR #89335)

[Brandon Wu via llvm-commits]

4vtomat wrote:

Except for extension lists, are we also going to auto generate implication lists in `RISCVISAInfo.cpp`?

https://github.com/llvm/llvm-project/pull/89335