[compiler-rt] [compiler-rt][RISC-V] ILP32E/LP64E Save/Restore Grouping (PR #95398)

[Kito Cheng via llvm-commits]

kito-cheng wrote:

That's two different flavor of implementation, one for smaller code size (but few byte smaller only) , and another one is smaller stack usage, I have to say I like the later one which is this PR :P 

Honestly I don't have too much memory about why we chose that approach, my best guess it could reuse same CFI logic, however...ironically I found the CFI directive is wrong on the GCC side for save restore routines for ilp32e...so I think it's good timing to document that down on toolchain conventions and then I gonna fix that on GCC side.

https://github.com/llvm/llvm-project/pull/95398