These intrinsics actually are zeroing, so we should be upfront
that these still return a valid value in reality. At most,
we might in the future want to use a "freezing" semantics here.
In any case, they are definitely not returning MaybeUninit,
or any other possibly-poison value.
This is a follow-up to #1345 where these appeared as unstable in the
standard library docs because they are only stabilized for ARM. They
were missed in the original PR.
- Fix a typo in the feature name
- Update docs to reflect changes in behavior on invalid ordering in
stabilized PR: invalid ordering is no longer UB, just causes panic as
well as compare_exchange
This commit adds intrinsics to the `wasm32` to support the [relaxed SIMD
proposal][proposal]. These are added with the same naming conventions of
existing simd-related intrinsics for wasm which is similar to the
instruction name but matches sign in a few places.
This additionally updates Wasmtime to execute tests with support for the
relaxed simd proposal. No release has been made yet so this uses the
`dev` release, and I can make a PR in April when the support in Wasmtime
has been released to an official release. The `wasmprinter` crate is
also updated to understand these instruction opcodes as well.
Documentation has been added for all intrinsics, but tests have only
been added for some of them so far. I hope to follow-up later with more
tests.
[proposal]: https://github.com/WebAssembly/relaxed-simd
```
warning: the feature `cmpxchg16b_target_feature` has been stable since 1.69.0-nightly and no longer requires an attribute to enable
--> crates/core_arch/src/lib.rs:24:5
|
24 | cmpxchg16b_target_feature,
| ^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: `#[warn(stable_features)]` on by default
warning: the feature `target_feature_11` has been stable since 1.69.0-nightly and no longer requires an attribute to enable
--> crates/core_arch/src/lib.rs:34:5
|
34 | target_feature_11,
| ^^^^^^^^^^^^^^^^^
```
Samsung Exynos 9810 has a bug that big and little cores have different
ISAs. And on older Android (pre-9), the kernel incorrectly reports
that features available only on some cores are available on all cores.
https://reviews.llvm.org/D114523
f16c_target_feature was recently stabilised.
This fixes a warning that results in a CI failure (due to `-D
stable-features`) with current nightly Rust.
The tests can run if and only if the target_features for the
corresponding intrinsics are detected at run-time, so make sure that the
tests have an appropriate `simd_test()`.
This fixes some failures due to tests running when they shouldn't. For
example, some tests would fail on hardware that lacks "fcma".
