mirror of https://github.com/rust-lang/rust.git
acb4e8b625
Implement a first version of RFC 3525: struct target features This PR is an attempt at implementing https://github.com/rust-lang/rfcs/pull/3525, behind a feature gate `struct_target_features`. There's obviously a few tasks that ought to be done before this is merged; in no particular order: - add proper error messages - add tests - create a tracking issue for the RFC - properly serialize/deserialize the new target_features field in `rmeta` (assuming I even understood that correctly :-)) That said, as I am definitely not a `rustc` expert, I'd like to get some early feedback on the overall approach before fixing those things (and perhaps some pointers for `rmeta`...), hence this early PR :-) Here's an example piece of code that I have been using for testing - with the new code, the calls to intrinsics get correctly inlined: ```rust #![feature(struct_target_features)] use std::arch::x86_64::*; /* // fails to compile #[target_feature(enable = "avx")] struct Invalid(u32); */ #[target_feature(enable = "avx")] struct Avx {} #[target_feature(enable = "sse")] struct Sse(); /* // fails to compile extern "C" fn bad_fun(_: Avx) {} */ /* // fails to compile #[inline(always)] fn inline_fun(_: Avx) {} */ trait Simd { fn do_something(&self); } impl Simd for Avx { fn do_something(&self) { unsafe { println!("{:?}", _mm256_setzero_ps()); } } } impl Simd for Sse { fn do_something(&self) { unsafe { println!("{:?}", _mm_setzero_ps()); } } } struct WithAvx { #[allow(dead_code)] avx: Avx, } impl Simd for WithAvx { fn do_something(&self) { unsafe { println!("{:?}", _mm256_setzero_ps()); } } } #[inline(never)] fn dosomething<S: Simd>(simd: &S) { simd.do_something(); } fn main() { /* // fails to compile Avx {}; */ if is_x86_feature_detected!("avx") { let avx = unsafe { Avx {} }; dosomething(&avx); dosomething(&WithAvx { avx }); } if is_x86_feature_detected!("sse") { dosomething(&unsafe { Sse {} }) } } ``` Tracking: - https://github.com/rust-lang/rust/issues/129107 |
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