[llvm] [RISCV] Add experimental support for making i32 a legal type on RV64 in SelectionDAG. (PR #70357)

[Wang Pengcheng via llvm-commits]

wangpc-pp wrote:

I remember that I have tried to do this about one year ago (after adding `n32` to RV64 datalayout) but failed because some llvm-testsuite cases weren't passed. Can you run llvm-testsuite and see if there are some failures?

https://github.com/llvm/llvm-project/pull/70357