[llvm] [LoongArch] Enable alias analysis by default (PR #114980)

[Lu Weining via llvm-commits]

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SixWeining wrote:

> define void @merge_load_store(ptr noalias nocapture noundef readonly align 1 dereferenceable(8) %src, ptr noalias nocapture noundef writeonly align 1 dereferenceable(8) %dst) unnamed_addr {

Are all these attributes beside `noalias` necessary for this test?

https://github.com/llvm/llvm-project/pull/114980