[llvm] [InstCombine] Simplify and/or of icmp eq with op replacement (PR #70335)

[via llvm-commits]

mikaelholmen wrote:

Ok. I *think* this exposes a miscompile with this patch:
```opt -passes=instcombine ic.ll -o - -S```
With the patch we get
```
land.end:                                         ; preds = %for.body
  br i1 poison, label %cond.false, label %cond.end
```
which looks broken to me.
It can surely be further reduced but I didn't want to risk messing something up now.
[ic.ll.gz](https://github.com/llvm/llvm-project/files/13234594/ic.ll.gz)


https://github.com/llvm/llvm-project/pull/70335