Broken CI SIMD and wasm checks on master: unknown feature llvm_asm

[alamb]

The CI wasm and SIMD tests are now failing on master:

https://github.com/apache/arrow-rs/runs/4852992130?check_suite_focus=true
https://github.com/apache/arrow-rs/runs/4852992553?check_suite_focus=true

complaining about missing llvm_asm, which appears to relate to rust-lang/packed_simd#340 as pointed out by @gangliao on #1195

Originally posted by @tustvold in #1189 (comment)

[alamb]

Reverting #1189 did not appear to fix the issue. Perhaps another crate accidentally released a breaking change

[jorgecarleitao]

We are observing the same on arrow2. This seems to be upstream :(

[alamb]

I plan to look into this more carefully tomorrow morning (US eastern time)

[alamb]

I am pretty confident that this is an issue in packed_simd -- in the sense that the library depends on some feature in rust nightly which has since been removed. Here is a PR that should fix it:

rust-lang/packed_simd#341

In theory if we can get the maintainers to release an updated version this will be fixed for us

[alamb]

We can always follow the lead of arrow2 here if no one is willing to publish a new fix for packed_simd and switch to stdsimd -- jorgecarleitao/arrow2#747

I suppose "code that compiles but is slower" is better than "code that doesn't compile"

[alamb]

Datapoints:

Works:

cargo +nightly-2021-12-08-x86_64-apple-darwin test -p arrow --features=simd
cargo +nightly-2022-01-14-x86_64-apple-darwin test -p arrow --features=simd
cargo +nightly-2022-01-15-x86_64-apple-darwin test -p arrow --features=simd
cargo +nightly-2022-01-16-x86_64-apple-darwin test -p arrow --features=simd
cargo +nightly-2022-01-17-x86_64-apple-darwin test -p arrow --features=simd

Doesn't work:

cargo +nightly test -p arrow --features=simd

(aka I think it was the nightly version that was released today -- 2022-01-18)

[tustvold]

I think this can be closed now