llvm backend should use unordered atomics for load/store to shared memory

[programmerjake]

iirc WebAssembly requires non-atomic load/store operations to have somewhat sane results when there is a data race, but in llvm data races of non-atomic load/stores are UB. the fix is to use llvm's unordered atomic ordering which is specificly designed for cases like this: https://releases.llvm.org/14.0.0/docs/Atomics.html#unordered

[syrusakbary]

Thanks for opening the issue! We'll take a look on this approach after releasing Wasmer 3.0

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[programmerjake]

version 3.0 was released, since this fixes UB in LLVM, I think it's worth taking a closer look at