[llvm] [clang] [RISCV] CodeGen of RVE and ilp32e/lp64e ABIs (PR #76777)

[Kito Cheng via cfe-commits]

kito-cheng wrote:

Hmmm, RISC-V ISA is growth after https://github.com/riscv-non-isa/riscv-elf-psabi-doc/pull/257 again, I mean...we have zfinx and zdinx, which is also valid combination with rv32e/rv64e, so we may need to revise ilp32e ABI again on the psABI side, but my intention is not to block this PR.

Anyway, I think we could track that on psABI repo, and we...already has an old issue to track that: https://github.com/riscv-non-isa/riscv-elf-psabi-doc/issues/269 

https://github.com/llvm/llvm-project/pull/76777