Auto merge of #93146 - workingjubilee:use-std-simd, r=Mark-Simulacrum

pub use std::simd::StdFloat;

Syncs portable-simd up to commit rust-lang/portable-simd@03f6fbb21e6050da2a05b3ce8f480c020b384916,
Diff: https://github.com/rust-lang/portable-simd/compare/533f0fc81ab9ba097779fcd27c8f9ea12261fef5...03f6fbb21e6050da2a05b3ce8f480c020b384916

This sync requires a little bit more legwork because it also introduces a trait into `std::simd`, so that it is no longer simply a reexport of `core::simd`. Out of simple-minded consistency and to allow more options, I replicated the pattern for the way `core::simd` is integrated in the first place, however this is not necessary if it doesn't acquire any interdependencies inside `std`: it could be a simple crate reexport. I just don't know yet if that will happen or not.

To summarize other misc changes:
- Shifts no longer panic, now wrap on too-large shifts (like `Simd` integers usually do!)
- mask16x32 will now be many i16s, not many i32s... 🙃
- `#[must_use]` is spread around generously
- Adjusts division, float min/max, and `Mask::{from,to}_array` internally to be faster
- Adds the much-requested `Simd::cast::<U>` function (equivalent to `simd.to_array().map(|lane| lane as U)`)

3 files changed, 37 insertions, 12 deletions

diff --git a/src/test/ui/simd/libm_std_can_float.rs b/src/test/ui/simd/libm_std_can_float.rs
new file mode 100644
index 00000000000..6a844e7120e
--- /dev/null
+++ b/src/test/ui/simd/libm_std_can_float.rs
@@ -0,0 +1,23 @@
+// run-pass
+
+// This is the converse of the other libm test.
+#![feature(portable_simd)]
+use std::simd::f32x4;
+use std::simd::StdFloat;
+
+// For SIMD float ops, the LLIR version which is used to implement the portable
+// forms of them may become calls to math.h AKA libm. So, we can't guarantee
+// we can compile them for #![no_std] crates.
+//
+// However, we can expose some of these ops via an extension trait.
+fn main() {
+    let x = f32x4::from_array([0.1, 0.5, 0.6, -1.5]);
+    let x2 = x + x;
+    let _xc = x.ceil();
+    let _xf = x.floor();
+    let _xr = x.round();
+    let _xt = x.trunc();
+    let _xfma = x.mul_add(x, x);
+    let _xsqrt = x.sqrt();
+    let _ = x2.abs() * x2;
+}
diff --git a/src/test/ui/simd/portable-intrinsics-arent-exposed.rs b/src/test/ui/simd/portable-intrinsics-arent-exposed.rs
index 4d759032355..667c8b67b1d 100644
--- a/src/test/ui/simd/portable-intrinsics-arent-exposed.rs
+++ b/src/test/ui/simd/portable-intrinsics-arent-exposed.rs
@@ -1,7 +1,8 @@
 // May not matter, since people can use them with a nightly feature.
 // However this tests to guarantee they don't leak out via portable_simd,
 // and thus don't accidentally get stabilized.
-use std::simd::intrinsics; //~ERROR E0603
+use core::simd::intrinsics; //~ERROR E0433
+use std::simd::intrinsics; //~ERROR E0432
 
 fn main() {
     ()
diff --git a/src/test/ui/simd/portable-intrinsics-arent-exposed.stderr b/src/test/ui/simd/portable-intrinsics-arent-exposed.stderr
index 9ac73eca193..f568aa04295 100644
--- a/src/test/ui/simd/portable-intrinsics-arent-exposed.stderr
+++ b/src/test/ui/simd/portable-intrinsics-arent-exposed.stderr
@@ -1,15 +1,16 @@
-error[E0603]: module `intrinsics` is private
-  --> $DIR/portable-intrinsics-arent-exposed.rs:4:16
+error[E0433]: failed to resolve: maybe a missing crate `core`?
+  --> $DIR/portable-intrinsics-arent-exposed.rs:4:5
    |
-LL | use std::simd::intrinsics;
-   |                ^^^^^^^^^^ private module
-   |
-note: the module `intrinsics` is defined here
-  --> $SRC_DIR/core/src/lib.rs:LL:COL
+LL | use core::simd::intrinsics;
+   |     ^^^^ maybe a missing crate `core`?
+
+error[E0432]: unresolved import `std::simd::intrinsics`
+  --> $DIR/portable-intrinsics-arent-exposed.rs:5:5
    |
-LL |     pub use crate::core_simd::simd::*;
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | use std::simd::intrinsics;
+   |     ^^^^^^^^^^^^^^^^^^^^^ no `intrinsics` in `simd`
 
-error: aborting due to previous error
+error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0603`.
+Some errors have detailed explanations: E0432, E0433.
+For more information about an error, try `rustc --explain E0432`.