[llvm] [EarlyCSE] Compare GEP instructions based on offset (PR #65875)

[via llvm-commits]

DianQK wrote:

> I'm wondering, would we be able to achieve similar results if we add a `DenseMap<GetElementPtrInst *, APInt>` cache for the offset but otherwise keep the previous code structure? Or would the extra hash lookup make this slow again?

I feel like I misunderstood. Do you mean putting the GEP back into `SimpleValue`? And then create a global (or EarlyCSE only) cache value?

https://github.com/llvm/llvm-project/pull/65875