[llvm] [LAA] Fix non-NFC parts of 1aded51 (PR #160701)

[Ramkumar Ramachandra via llvm-commits]

artagnon wrote:

> Hi again @artagnon
> 
> After some more testing we see that the following starts crashing with this patch and it still crashes on trunk ([d48bda5](https://github.com/llvm/llvm-project/commit/d48bda5421c5af9baa5bc98ba4e3a453937ff96a)): `clang -O2 -fwrapv bbi-110970.c -c` Result:

Thanks again for the subtle bug report with `-fwrapv`. I think it's highly unfortunate, and this is code to blame:

```cpp
    if (!LoopGuards)
      LoopGuards.emplace(
          ScalarEvolution::LoopGuards::collect(InnermostLoop, SE));
    Dist = SE.applyLoopGuards(Dist, *LoopGuards);
```

Will fix in the morning.

https://github.com/llvm/llvm-project/pull/160701