[llvm] [AArch64] Use LD1/ST1 in strict-align mode (PR #211513)

[Peter Smith via llvm-commits]

smithp35 wrote:

> Do we think this will cause problems for users? It has never been clear to me if strict-align is purely about what the architecture considers aligned in some mode or what the frontend considers aligned. I don't know of any immediate places this would cause problems.

In my experience it has been just about alignment. There is sometimes a user that has a memory interface that has additional restrictions, such as not supporting instructions with multiple memory accesses. For example memory mapped peripherals. This does tend to be a narrow use case, and we've normally relied on the user to disable neon/advanced-simd if these instructions would cause problems.

https://github.com/llvm/llvm-project/pull/211513