[llvm] [InstCombine] Fold fcmp ogt (x - y), 0 into fcmp ogt x, y #85245 (PR #85506)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm commented:

essentially LGTM, except the hasOneUse duplication makes less sense than moving the whole pattern check before the predicate test switch with the isKnownNeverInf checks 

https://github.com/llvm/llvm-project/pull/85506