[llvm] [InstCombine] Fold `(x == y) ? 0 : (x > y ? 1 : -1)` into `ucmp/scmp(x,y)` (PR #107314)

[Volodymyr Vasylkun via llvm-commits]

Poseydon42 wrote:

Rebased onto #107769. @dtcxzyw, can you please rerun the benchmark to see if the regression is fully gone. If that's the case I reckon we can go ahead and merge this and fix the other regression later as it seems to be less common. 

https://github.com/llvm/llvm-project/pull/107314