[llvm] [RISCV] Combine ({s,u}{div,rem} (zext, zext)) -> (zext ({s,u}{div,rem} (zext, zext))) (PR #86779)

[Wang Pengcheng via llvm-commits]

https://github.com/wangpc-pp approved this pull request.

> However I'm assuming that div/rem are expensive enough that by reducing their EMUL we will gain back the cost.

And we have reduced the EEW too. Most of implementations will have smaller cost if EEW is smaller.
LGTM!

https://github.com/llvm/llvm-project/pull/86779