[llvm] [GISel][RISCV] Legalize `G_{U|S}DIVREM` (PR #93067)

[Craig Topper via llvm-commits]

topperc wrote:

> Is there any good reason why it always generates separate lib calls for div and rem rather than a single line call for divrem?

The divrem expansion in GISel probably splits its into div and rem and then each get legalized separate.

It's very weird to me that GISel combiner creates DIVREM when it needs to be expanded. That's not what SelectionDAG does.

https://github.com/llvm/llvm-project/pull/93067