[llvm] [IRBuilder] Fold binary intrinsics (PR #80743)

[Nikita Popov via llvm-commits]

https://github.com/nikic requested changes to this pull request.

Please remove the changes to IR/ConstantFold. I'm not willing to duplicate constant folding logic in there. If we *really* wanted to we could *move* logic there, but we should not copy it.

https://github.com/llvm/llvm-project/pull/80743