[llvm] [InstCombine] Do not keep samesign when speculatively executing icmps (PR #127007)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

> Is the problem simplifyICmpWithMinMax?

No. We simplify `icmp samesign ult X, -46` into false according to the dominating condition `icmp sgt i8 %x, -2`.

> Does it call simplifyICmpWithConstant, and is the UseInstrInfo check there?

I mean we should drop samesign at the beginning of `simplifyICmpInst` if `UseInstrInfo` is false.


https://github.com/llvm/llvm-project/pull/127007