Allow the first argument of #[simd] functions to be f32x4<S> and such

CHANGELOG.md

@@ -16,6 +16,7 @@ This release has an [MSRV][] of 1.89.
 ### Added
 
 - Added `Native<S>` to `SimdFloatElement` and `SimdIntElement` to select native-width vectors in scalar-generic code. 
+- Added the public `ExtractToken` trait for SIMD tokens, vectors, masks, references, and user-defined wrappers. `#[simd]` now extracts its token from the first non-receiver parameter, allowing vector arguments without a separate token parameter.
 - Added `reverse` for all SIMD vector and mask types. ([#356][] by [@Shnatsel][])
 - Added `rotate_elements_left` and `rotate_elements_right` to mask types. Rotations wrap the offset, matching the existing non-mask vector operations. ([#360][] by [@Shnatsel][])
 - Added lane-wise `saturating_add` and `saturating_sub` for all integer vector types and backends. ([#352][] by [@Shnatsel][])
@@ -29,6 +30,7 @@ This release has an [MSRV][] of 1.89.
 
 ### Changed
 
+- Breaking change: `witness()` has moved from `SimdBase` and `SimdMask` to their new `ExtractToken` supertrait and has been renamed to `token()`.
 - Breaking change: `SimdBase::N` and `SimdMask::N` have been renamed to `LEN`, matching the `std::simd` naming. ([#366][] by [@Shnatsel][])
 - Breaking change: `SimdBase::as_array` now borrows the vector and returns an array reference, while owned extraction has moved to `to_array`. The old `as_array_ref` and `as_array_mut` methods have been replaced by `as_array` and `as_mut_array`, matching the `std::simd` API. ([#351][] by [@Shnatsel][])
 - Breaking change: `abs` has moved from `SimdFloat` to `SimdBase` and is now available on integer vectors. Signed integers use wrapping absolute value, leaving the minimum representable value unchanged; unsigned integers are unchanged. ([#371][] by [@Shnatsel][])

fearless_simd/src/generated/avx2.rs

@@ -42,6 +42,13 @@ impl Avx2 {
     }
 }
 impl Seal for Avx2 {}
+impl ExtractToken for Avx2 {
+    type S = Self;
+    #[inline]
+    fn token(&self) -> Self {
+        *self
+    }
+}
 impl ArchTypes for Avx2 {
     type f32x4 = crate::support::Aligned128<__m128>;
     type i8x16 = crate::support::Aligned128<__m128i>;

fearless_simd/src/generated/avx512.rs

@@ -52,6 +52,13 @@ impl Avx512 {
     }
 }
 impl Seal for Avx512 {}
+impl ExtractToken for Avx512 {
+    type S = Self;
+    #[inline]
+    fn token(&self) -> Self {
+        *self
+    }
+}
 impl ArchTypes for Avx512 {
     type f32x4 = crate::support::Aligned128<__m128>;
     type i8x16 = crate::support::Aligned128<__m128i>;

fearless_simd/src/generated/fallback.rs

@@ -124,6 +124,13 @@ impl Fallback {
     }
 }
 impl Seal for Fallback {}
+impl ExtractToken for Fallback {
+    type S = Self;
+    #[inline]
+    fn token(&self) -> Self {
+        *self
+    }
+}
 impl ArchTypes for Fallback {
     type f32x4 = crate::support::Aligned128<[f32; 4usize]>;
     type i8x16 = crate::support::Aligned128<[i8; 16usize]>;

fearless_simd/src/generated/neon.rs

@@ -37,6 +37,13 @@ impl Neon {
     }
 }
 impl Seal for Neon {}
+impl ExtractToken for Neon {
+    type S = Self;
+    #[inline]
+    fn token(&self) -> Self {
+        *self
+    }
+}
 impl ArchTypes for Neon {
     type f32x4 = crate::support::Aligned128<float32x4_t>;
     type i8x16 = crate::support::Aligned128<int8x16_t>;

fearless_simd/src/generated/simd_trait.rs

@@ -4,8 +4,8 @@
 // This file is autogenerated by fearless_simd_gen
 
 use crate::{
-    Bytes, Level, Select, SimdCvtFloat, SimdCvtTruncate, SimdElement, SimdFloatElement, SimdFrom,
-    SimdIntElement, SimdInto, SimdNarrow, SimdWiden, seal::Seal,
+    Bytes, ExtractToken, Level, Select, SimdCvtFloat, SimdCvtTruncate, SimdElement,
+    SimdFloatElement, SimdFrom, SimdIntElement, SimdInto, SimdNarrow, SimdWiden, seal::Seal,
 };
 use crate::{
     f32x4, f32x8, f32x16, f64x2, f64x4, f64x8, i8x16, i8x32, i8x64, i16x8, i16x16, i16x32, i32x4,
@@ -50,7 +50,16 @@ use core::fmt::Debug;
 #[doc = r" });"]
 #[doc = r" ```"]
 pub trait Simd:
-    Sized + Clone + Copy + Send + Sync + Debug + Seal + arch_types::ArchTypes + 'static
+    ExtractToken<S = Self>
+    + Sized
+    + Clone
+    + Copy
+    + Send
+    + Sync
+    + Debug
+    + Seal
+    + arch_types::ArchTypes
+    + 'static
 {
     #[doc = r" A native-width SIMD vector of [`f32`]s."]
     type f32s: SimdFloat<
@@ -9564,7 +9573,8 @@ pub(crate) mod arch_types {
 }
 #[doc = r" Base functionality implemented by all SIMD vectors."]
 pub trait SimdBase<S: Simd>:
-    Copy
+    ExtractToken<S = S>
+    + Copy
     + Sync
     + Send
     + Debug
@@ -9622,8 +9632,6 @@ pub trait SimdBase<S: Simd>:
         + AsRef<[Self::Element]>
         + AsMut<[Self::Element]>
         + From<Self>;
-    #[doc = r" Get the [`Simd`] implementation associated with this type."]
-    fn witness(&self) -> S;
     fn as_slice(&self) -> &[Self::Element];
     fn as_mut_slice(&mut self) -> &mut [Self::Element];
     #[doc = r" Create a SIMD vector from a slice."]
@@ -9896,7 +9904,7 @@ pub trait SimdBase<S: Simd>:
     #[doc = r" If `OFFSET` is greater than or equal to `Self::LEN`, all lanes are filled with `padding`."]
     #[inline(always)]
     fn shift_elements_right<const OFFSET: usize>(self, padding: Self::Element) -> Self {
-        let padding = Self::splat(self.witness(), padding);
+        let padding = Self::splat(self.token(), padding);
         match Self::LEN.saturating_sub(OFFSET) {
             0 => padding.slide::<0>(self),
             1 => padding.slide::<1>(self),
@@ -10131,7 +10139,8 @@ pub trait SimdInt<S: Simd>:
 #[doc = r" current backends may use all-zero/all-one integer vectors internally, while future"]
 #[doc = r" predicate-register backends may use a compact representation."]
 pub trait SimdMask<S: Simd>:
-    Copy
+    ExtractToken<S = S>
+    + Copy
     + Sync
     + Send
     + 'static
@@ -10152,8 +10161,6 @@ pub trait SimdMask<S: Simd>:
     type Element: SimdElement;
     #[doc = r" This mask type's lane count."]
     const LEN: usize;
-    #[doc = r" Get the [`Simd`] implementation associated with this type."]
-    fn witness(&self) -> S;
     #[doc = r" Create a SIMD mask with all lanes set to the given boolean value."]
     fn splat(simd: S, val: bool) -> Self;
     #[doc = r" Create a mask from a compact bitmask."]