Remove portable_simd

Stand-in for a backport of "Sync portable-simd to remove autosplats #91484".

Author: Mark-Simulacrum

library/core/src/lib.rs

@@ -398,27 +398,4 @@ pub mod arch {
     }
 }
 
-// Pull in the `core_simd` crate directly into libcore. The contents of
-// `core_simd` are in a different repository: rust-lang/portable-simd.
-//
-// `core_simd` depends on libcore, but the contents of this module are
-// set up in such a way that directly pulling it here works such that the
-// crate uses this crate as its libcore.
-#[path = "../../portable-simd/crates/core_simd/src/mod.rs"]
-#[allow(missing_debug_implementations, dead_code, unsafe_op_in_unsafe_fn, unused_unsafe)]
-#[allow(rustdoc::bare_urls)]
-#[unstable(feature = "portable_simd", issue = "86656")]
-#[cfg(not(all(miri, doctest)))] // Miri does not support all SIMD intrinsics
-#[cfg(not(bootstrap))]
-mod core_simd;
-
-#[doc = include_str!("../../portable-simd/crates/core_simd/src/core_simd_docs.md")]
-#[unstable(feature = "portable_simd", issue = "86656")]
-#[cfg(not(all(miri, doctest)))] // Miri does not support all SIMD intrinsics
-#[cfg(not(bootstrap))]
-pub mod simd {
-    #[unstable(feature = "portable_simd", issue = "86656")]
-    pub use crate::core_simd::simd::*;
-}
-
 include!("primitive_docs.rs");

library/core/tests/lib.rs

@@ -61,7 +61,6 @@
 #![feature(never_type)]
 #![feature(unwrap_infallible)]
 #![feature(result_into_ok_or_err)]
-#![cfg_attr(not(bootstrap), feature(portable_simd))]
 #![feature(ptr_metadata)]
 #![feature(once_cell)]
 #![feature(unsized_tuple_coercion)]
@@ -107,8 +106,6 @@ mod pattern;
 mod pin;
 mod ptr;
 mod result;
-#[cfg(not(bootstrap))]
-mod simd;
 mod slice;
 mod str;
 mod str_lossy;

library/core/tests/simd.rs

@@ -323,7 +323,6 @@
 #![feature(panic_internals)]
 #![feature(panic_unwind)]
 #![feature(pin_static_ref)]
-#![cfg_attr(not(bootstrap), feature(portable_simd))]
 #![feature(prelude_import)]
 #![feature(ptr_internals)]
 #![feature(rustc_attrs)]
@@ -475,9 +474,6 @@ pub use core::pin;
 pub use core::ptr;
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use core::result;
-#[unstable(feature = "portable_simd", issue = "86656")]
-#[cfg(not(bootstrap))]
-pub use core::simd;
 #[unstable(feature = "async_stream", issue = "79024")]
 pub use core::stream;
 #[stable(feature = "i128", since = "1.26.0")]

library/std/src/lib.rs

@@ -4,9 +4,6 @@ error[E0277]: the trait bound `&[i8]: From<&[u8]>` is not satisfied
 LL |     let _: &[i8] = data.into();
    |                         ^^^^ the trait `From<&[u8]>` is not implemented for `&[i8]`
    |
-   = help: the following implementations were found:
-             <[T; LANES] as From<Simd<T, LANES>>>
-             <[bool; LANES] as From<Mask<T, LANES>>>
    = note: required because of the requirements on the impl of `Into<&[i8]>` for `&[u8]`
 
 error: aborting due to previous error