[llvm] [SLP]Convert compares from zexts, promoted to selects, to inversed op, if improves codegen (PR #181580)

[Mikael Holmen via llvm-commits]

mikaelholmen wrote:

> > Second miscompile (at commit [5a4a1f4](https://github.com/llvm/llvm-project/commit/5a4a1f41b1dd1410feaf78457dec86edccb9ea99)) seen with: `opt -passes=slp-vectorizer bbi-115289.ll -S -o -`
> > The input adds 0 to the return value. The slp-vectorizer output adds 8. [bbi-115289.ll.gz](https://github.com/user-attachments/files/25439905/bbi-115289.ll.gz)
> > I can't help but feel that the original patch would have needed better testing to begin with and still does.
> > Now revert?
> 
> Fixed in [95a960d](https://github.com/llvm/llvm-project/commit/95a960daa0ebc4b582dbfebed26981552d94a3cd)

I've verified that fix solved the second problem.

https://github.com/llvm/llvm-project/pull/181580