[llvm] LICM: hoist BO assoc when (C1 op LV) op C2 (PR #106999)

[Ramkumar Ramachandra via llvm-commits]

artagnon wrote:

> > > You can just assert that the op is commutative (after the associativity check). In general, all associative ops we support are also commutative.
> > 
> > 
> > Little confused by this. Aren't `FAdd` and `FMul` commutative, but not associative?
> 
> Sorry, I should have been clearer: if we check for associativity before commutativity, does it mean that we don't see future work supporting `FAdd` and `FMul`?

I see this comment in the test, but it seems to be for the associative version:

```
; Don't hoist floating-point ops, even if they are associative. This would be
; valid, but is currently disabled.
```

https://github.com/llvm/llvm-project/pull/106999