[llvm] [InstCombine] Extend ADD+GEP->GEP+GEP combine to disjoint or. (PR #76981)

[Nikita Popov via llvm-commits]

nikic wrote:

This is basically fine, but I worry that this will introduce additional negative interactions with LICM, of the kind seen in llvm/test/Transforms/LoopVectorize/X86/float-induction-x86.ll. Maybe we should disable LICM reassociation for constant GEPs.

@dtcxzyw Does this appear to be a problem in IR diffs or not?

https://github.com/llvm/llvm-project/pull/76981