[llvm] [RISCV] Prefer (select (x < 0), y, z) -> x >> (XLEN - 1) & (y - z) + z even with Zicond. (PR #125772)

[Craig Topper via llvm-commits]

topperc wrote:

> LGTM. Thank you! Please add some tests to demonstrate the change.

There should be test changes in the second commit. The first commit contains a new RUN lines with Zicond to an existing test.

https://github.com/llvm/llvm-project/pull/125772