[llvm] LICM: extend hoist BO assoc to mul case (PR #106991)

[Nikita Popov via llvm-commits]

================
@@ -119,7 +211,31 @@ loop:
   br label %loop
 }
 
-; Don't fold if the ops are different (even if they are both associative).
+; Hoist MUL and drop NSW if both ops have it.
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nikic wrote:

```suggestion
; Hoist MUL and drop NSW even if both ops have it.
```

https://github.com/llvm/llvm-project/pull/106991