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rust/library/stdarch/crates/core_arch
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Alex Crichton 4e4a60b9d9
wasm: Lower alignment of all loads/stores (#1175) 
This changes wasm simd intrisnics which deal with memory to match clang
where they all are emitted with an alignment of 1. This is expected to
not impact performance since wasm engines generally ignore alignment as
it's just a hint. Otherwise this can increase safety slightly when used
from Rust since if an unaligned pointer was previously passed in that
could result in UB on the LLVM side. This means that the intrinsics are
slighly more usable in more situations than before.

It's expected that if higher alignment is desired then programs will not
use these intrinsics but rather the component parts. For example instead
of `v128_load` you'd just load the pointer itself (and loading from a
pointer in Rust automatically assumes correct alignment). For
`v128_load64_splat` you'd do a load followed by a splat operation, which
LLVM should optimized into a `v128.load64_splat` instruction with the
desired alignment. LLVM doesn't fully support some optimizations (such
as optimizing `v128.load16_lane` from component parts) but that's
expected to be a temporary issue. Additionally we don't have a way of
configuring the alignment on operations that otherwise can't be
decomposed into their portions (such as with `i64x2_load_extend_u32x2`),
but we can ideally cross such a bridge when we get there if anyone ever
needs the alignment configured there.
2021-05-28 00:02:56 +01:00
..
src
wasm: Lower alignment of all loads/stores (#1175)
2021-05-28 00:02:56 +01:00
tests
Fix some clippy lints (#937)
2020-11-02 00:53:39 +00:00
avx512bw.md
avx512bw (#1014)
2021-02-25 20:38:05 +00:00
avx512f.md
Avx512f avx512vl (#1010)
2021-02-23 01:33:16 +00:00
avx512vbmi2.md
Avx512f avx512vl (#1010)
2021-02-23 01:33:16 +00:00
build.rs
Update WebAssembly SIMD/Atomics (#1073)
2021-03-11 23:30:30 +00:00
Cargo.toml
Replace cfg(dox) with cfg(doc) (#920)
2020-09-29 23:57:19 +01:00
LICENSE-APACHE
…
LICENSE-MIT
…
README.md
Remove azure pipelines badges
2019-10-10 12:42:41 +02:00
rustfmt.toml
Replace rustfmt::skip custom inner attribute with rustfmt.toml
2019-10-26 18:46:22 +02:00

README.md

core::arch - Rust's core library architecture-specific intrinsics

core_arch_crate_badge core_arch_docs_badge

The core::arch module implements architecture-dependent intrinsics (e.g. SIMD).

Usage

core::arch is available as part of libcore and it is re-exported by libstd. Prefer using it via core::arch or std::arch than via this crate. Unstable features are often available in nightly Rust via the feature(stdsimd).

Using core::arch via this crate requires nightly Rust, and it can (and does) break often. The only cases in which you should consider using it via this crate are:

  • if you need to re-compile core::arch yourself, e.g., with particular target-features enabled that are not enabled for libcore/libstd. Note: if you need to re-compile it for a non-standard target, please prefer using xargo and re-compiling libcore/libstd as appropriate instead of using this crate.

  • using some features that might not be available even behind unstable Rust features. We try to keep these to a minimum. If you need to use some of these features, please open an issue so that we can expose them in nightly Rust and you can use them from there.

Documentation

License

core_arch is primarily distributed under the terms of both the MIT license and the Apache License (Version 2.0), with portions covered by various BSD-like licenses.

See LICENSE-APACHE, and LICENSE-MIT for details.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in core_arch by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.