Previously we only disabled these warnings for SSE2, which is assumed
enabled on x86-64, but it looks like new nightly compilers are also
assuming SSE4.1 on macOS. Disabling these warnings across all the
detection functions accounts for that, and it also gets rid of some
warnings that you'd see if you used RUSTFLAGS='-C target-cpu=native'.
This is quite hard to trigger, because SSE2 has been guaranteed for a
long time. But you could trigger it this way:
rustup target add i686-unknown-linux-musl
RUSTFLAGS="-C target-cpu=i386" cargo build --target i686-unknown-linux-musl
Note a relevant gotcha though: The `cross` tool will not forward
environment variables like RUSTFLAGS to the container by default, so if
you're testing with `cross` you'll need to use the `rustc` command to
explicitly pass the flag, as I've done here in ci.yml. (Or you could
create a `Cross.toml` file, but I don't want to commit one of those if I
can avoid it.)
Wire up basic functions and features for SSE2 support using the SSE4.1 version
as a basis without implementing the SSE2 instructions yet.
* Cargo.toml: add no_sse2 feature
* benches/bench.rs: wire SSE2 benchmarks
* build.rs: add SSE2 rust intrinsics and assembly builds
* c/Makefile.testing: add SSE2 C and assembly targets
* c/README.md: add SSE2 to C build instructions
* c/blake3_c_rust_bindings/build.rs: add SSE2 C rust binding builds
* c/blake3_c_rust_bindings/src/lib.rs: add SSE2 C rust bindings
* c/blake3_dispatch.c: add SSE2 C dispatch
* c/blake3_impl.h: add SSE2 C function prototypes
* c/blake3_sse2.c: add SSE2 C intrinsic file starting with SSE4.1 version
* c/blake3_sse2_x86-64_{unix.S,windows_gnu.S,windows_msvc.asm}: add SSE2
assembly files starting with SSE4.1 version
* src/ffi_sse2.rs: add rust implementation using SSE2 C rust bindings
* src/lib.rs: add SSE2 rust intrinsics and SSE2 C rust binding rust SSE2 module
configurations
* src/platform.rs: add SSE2 rust platform detection and dispatch
* src/rust_sse2.rs: add SSE2 rust intrinsic file starting with SSE4.1 version
* tools/instruction_set_support/src/main.rs: add SSE2 feature detection
A helper function was incorrectly restricted to x86-only. CI doesn't
currently cover this, because benchmarks are nightly-only, and it's kind
of inconvenient to set RUSTC_BOOTSTRAP=1 through `cross` (which normally
doesn't propagate env vars). But maybe we should start...
There are two scenarios where compiling AVX-512 C or assembly code might
not work:
1. There might not be a C compiler installed at all. Most commonly this
is either in cross-compiling situations, or with the Windows GNU
target.
2. The installed C compiler might not support e.g. -mavx512f, because
it's too old.
In both of these cases, print a relevant warning, and then automatically
fall back to using the pure Rust intrinsics build.
Note that this only affects x86 targets. Other targets always use pure
Rust, unless the "neon" feature is enabled.
The biggest change here is that assembly implementations are enabled by
default.
Added features:
- "pure" (Pure Rust, with no C or assembly implementations.)
Removed features:
- "c" (Now basically the default.)
Renamed features;
- "c_prefer_intrinsics" -> "prefer_intrinsics"
- "c_neon" -> "neon"
Unchanged:
- "rayon"
- "std" (Still the only feature on by default.)
https://github.com/rust-lang/rust/issues/68905 is currently causing
nightly builds to fail, unless `--no-default-features` is used. This
change means that the default build will succeed, and the failure will
only happen when the "c_avx512" is enabled. The `b3sum` crate will still
fail to build on nightly, because it enables that feature, but most
callers should start succeeding on nightly.
The portable implementation was getting slowed down by converting back
and forth between words and bytes.
I made the corresponding change on the C side first
(12a37be8b5),
and as part of this commit I'm re-vendoring the C code. I'm also
exposing a small FFI interface to C so that blake3_neon.c can link
against portable.rs rather than blake3_portable.c, see c_neon.rs.
Ryo Onodera
Jack O'Connor
rsdy
Jack O'Connor
Matthew Krupcale