Add lane count marker type

Author: calebzulawski

crates/core_simd/src/comparisons.rs

@@ -1,13 +1,11 @@
-use crate::Vector;
+use crate::{LaneCount, SupportedLaneCount};
 
 macro_rules! implement_mask_ops {
     { $($vector:ident => $mask:ident ($inner_ty:ident),)* } => {
         $(
             impl<const LANES: usize> crate::$vector<LANES>
             where
-                crate::$vector<LANES>: Vector,
-                crate::$inner_ty<LANES>: Vector,
-                crate::$mask<LANES>: crate::Mask,
+                LaneCount<LANES>: SupportedLaneCount,
             {
                 /// Test if each lane is equal to the corresponding lane in `other`.
                 #[inline]

crates/core_simd/src/fmt.rs

@@ -35,7 +35,7 @@ macro_rules! impl_fmt_trait {
             $( // repeat trait
                 impl<const LANES: usize> core::fmt::$trait for crate::$type<LANES>
                 where
-                    Self: crate::Vector,
+                    crate::LaneCount<LANES>: crate::SupportedLaneCount,
                 {
                     fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
                         $format(self.as_ref(), f)

crates/core_simd/src/iter.rs

@@ -1,8 +1,10 @@
+use crate::{LaneCount, SupportedLaneCount};
+
 macro_rules! impl_traits {
     { $type:ident } => {
         impl<const LANES: usize> core::iter::Sum<Self> for crate::$type<LANES>
         where
-            Self: crate::Vector,
+            LaneCount<LANES>: SupportedLaneCount,
         {
             fn sum<I: core::iter::Iterator<Item = Self>>(iter: I) -> Self {
                 iter.fold(Default::default(), core::ops::Add::add)
@@ -11,7 +13,7 @@ macro_rules! impl_traits {
 
         impl<const LANES: usize> core::iter::Product<Self> for crate::$type<LANES>
         where
-            Self: crate::Vector,
+            LaneCount<LANES>: SupportedLaneCount,
         {
             fn product<I: core::iter::Iterator<Item = Self>>(iter: I) -> Self {
                 iter.fold(Default::default(), core::ops::Mul::mul)
@@ -20,7 +22,7 @@ macro_rules! impl_traits {
 
         impl<'a, const LANES: usize> core::iter::Sum<&'a Self> for crate::$type<LANES>
         where
-            Self: crate::Vector,
+            LaneCount<LANES>: SupportedLaneCount,
         {
             fn sum<I: core::iter::Iterator<Item = &'a Self>>(iter: I) -> Self {
                 iter.fold(Default::default(), core::ops::Add::add)
@@ -29,7 +31,7 @@ macro_rules! impl_traits {
 
         impl<'a, const LANES: usize> core::iter::Product<&'a Self> for crate::$type<LANES>
         where
-            Self: crate::Vector,
+            LaneCount<LANES>: SupportedLaneCount,
         {
             fn product<I: core::iter::Iterator<Item = &'a Self>>(iter: I) -> Self {
                 iter.fold(Default::default(), core::ops::Mul::mul)

crates/core_simd/src/lane_count.rs

@@ -0,0 +1,43 @@
+mod sealed {
+    pub trait Sealed {}
+}
+use sealed::Sealed;
+
+/// A type representing a vector lane count.
+pub struct LaneCount<const LANES: usize>;
+
+/// Helper trait for vector lane counts.
+pub trait SupportedLaneCount: Sealed {
+    /// The bitmask representation of a mask.
+    type BitMask: Copy + Default + AsRef<[u8]> + AsMut<[u8]>;
+
+    #[doc(hidden)]
+    type IntBitMask;
+}
+
+impl<const LANES: usize> Sealed for LaneCount<LANES> {}
+
+impl SupportedLaneCount for LaneCount<1> {
+    type BitMask = [u8; 1];
+    type IntBitMask = u8;
+}
+impl SupportedLaneCount for LaneCount<2> {
+    type BitMask = [u8; 1];
+    type IntBitMask = u8;
+}
+impl SupportedLaneCount for LaneCount<4> {
+    type BitMask = [u8; 1];
+    type IntBitMask = u8;
+}
+impl SupportedLaneCount for LaneCount<8> {
+    type BitMask = [u8; 1];
+    type IntBitMask = u8;
+}
+impl SupportedLaneCount for LaneCount<16> {
+    type BitMask = [u8; 2];
+    type IntBitMask = u16;
+}
+impl SupportedLaneCount for LaneCount<32> {
+    type BitMask = [u8; 4];
+    type IntBitMask = u32;
+}

crates/core_simd/src/lib.rs

@@ -21,10 +21,12 @@ mod comparisons;
 mod fmt;
 mod intrinsics;
 mod iter;
+mod math;
 mod ops;
 mod round;
 
-mod math;
+mod lane_count;
+pub use lane_count::*;
 
 mod masks;
 pub use masks::*;