[llvm] [InstCombine] Handle more scalable geps in EmitGEPOffset (PR #71699)

[Nikita Popov via llvm-commits]

nikic wrote:

> It appears that the `& PtrSizeMask` can be removed without altering any of the lit tests or any of the programs I tried across AArch64/Arm. Let me know if you think I should re-add it.

I think this is okay. I confirmed that the APInt uint64_t ctor will implicitly truncate the value, rather than asserting. As such, an explicit mask should not be necessary.

https://github.com/llvm/llvm-project/pull/71699