[llvm] [llvm-diff] Add associative on BinOp (PR #123314)

[Nikita Popov via llvm-commits]

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

I don't think this is correct behavior for llvm-diff. While this IR is semantically equivalent, LLVM may treat it differently, e.g. due to missing handling of commuted patterns. You could similarly argue that it should treat `mul %x, 2` and `shl %x, 1` as equal. They do the same thing, but they are not the same IR.

https://github.com/llvm/llvm-project/pull/123314