[llvm] [AArch64] merge index address with large offset into base address (PR #72187)

[David Green via llvm-commits]

davemgreen wrote:

> I don't prefer to DAG combine because it seems we need similar code to address load and store separately, may be performLOADCombine and performStoreCombine.

Could it share a similar method called from both performLOADCombine and performStoreCombine? I'm not sure if the opposite transform exists in DAG, but if it doesn't it should help only produce a single add.

https://github.com/llvm/llvm-project/pull/72187