[llvm] [AArch64] Mark Armv8.4-a LDAPUR* instructions as mayLoad (PR #171142)

[Nathan Corbyn via llvm-commits]

cofibrant wrote:

I should be able to post a patch including some ISel patterns for these instructions in the next couple of days. From these the compiler is able to infer `MayLoad` without this patch.

https://github.com/llvm/llvm-project/pull/171142