[llvm] [GlobalOpt] Look through non-PointerType constant expressions. (PR #125205)

[Eli Friedman via llvm-commits]

efriedma-quic wrote:

Say you have something like the following:

```
if ((uintptr_t)&g1 + 4 == (uintptr_t)&g2) {
  *(int*)((uintptr_t)&g1 + 4) = 10;
}
```

You have a write to g2, but the store itself doesn't mention g2 at all.

Maybe that's already broken even without your patch, though?  I'm suspicious of the way "IsCompared" works.

If comparisons aren't involved, I guess it's safe to recurse through ptrtoint/inttoptr?  At least, I can't come up with any way to break it in this context; like you say, it's conservatively correct.

https://github.com/llvm/llvm-project/pull/125205