pub use std::simd::StdFloat;

Make available the remaining float intrinsics that require runtime support
from a platform's libm, and thus cannot be included in a no-deps libcore,
by exposing them through a sealed trait, `std::simd::StdFloat`.

We might use the trait approach a bit more in the future, or maybe not.
Ideally, this trait doesn't stick around, even if so.
If we don't need to intermesh it with std, it can be used as a crate,
but currently that is somewhat uncertain.

Author: workingjubilee

std/src/lib.rs

@@ -313,6 +313,7 @@
 #![feature(panic_internals)]
 #![feature(panic_unwind)]
 #![feature(pin_static_ref)]
+#![feature(platform_intrinsics)]
 #![feature(portable_simd)]
 #![feature(prelude_import)]
 #![feature(ptr_as_uninit)]
@@ -465,8 +466,6 @@ 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")]
-pub use core::simd;
 #[unstable(feature = "async_stream", issue = "79024")]
 pub use core::stream;
 #[stable(feature = "i128", since = "1.26.0")]
@@ -513,6 +512,25 @@ pub mod time;
 #[unstable(feature = "once_cell", issue = "74465")]
 pub mod lazy;
 
+// Pull in `std_float` crate  into libstd. The contents of
+// `std_float` are in a different repository: rust-lang/portable-simd.
+#[path = "../../portable-simd/crates/std_float/src/lib.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
+mod std_float;
+
+#[cfg(not(all(miri, doctest)))] // Miri does not support all SIMD intrinsics
+#[doc = include_str!("../../portable-simd/crates/core_simd/src/core_simd_docs.md")]
+#[unstable(feature = "portable_simd", issue = "86656")]
+pub mod simd {
+    #[doc(inline)]
+    pub use crate::std_float::StdFloat;
+    #[doc(inline)]
+    pub use core::simd::*;
+}
+
 #[stable(feature = "futures_api", since = "1.36.0")]
 pub mod task {
     //! Types and Traits for working with asynchronous tasks.