1 files changed, 136 insertions, 0 deletions
diff --git a/library/portable-simd/crates/core_simd/src/elements/mut_ptr.rs b/library/portable-simd/crates/core_simd/src/elements/mut_ptr.rs
new file mode 100644
index 000000000..d87986b4a
--- /dev/null
+++ b/library/portable-simd/crates/core_simd/src/elements/mut_ptr.rs
@@ -0,0 +1,136 @@
+use super::sealed::Sealed;
+use crate::simd::{intrinsics, LaneCount, Mask, Simd, SimdPartialEq, SupportedLaneCount};
+
+/// Operations on SIMD vectors of mutable pointers.
+pub trait SimdMutPtr: Copy + Sealed {
+    /// Vector of `usize` with the same number of lanes.
+    type Usize;
+
+    /// Vector of `isize` with the same number of lanes.
+    type Isize;
+
+    /// Vector of constant pointers to the same type.
+    type ConstPtr;
+
+    /// Mask type used for manipulating this SIMD vector type.
+    type Mask;
+
+    /// Returns `true` for each lane that is null.
+    fn is_null(self) -> Self::Mask;
+
+    /// Changes constness without changing the type.
+    ///
+    /// Equivalent to calling [`pointer::cast_const`] on each lane.
+    fn cast_const(self) -> Self::ConstPtr;
+
+    /// Gets the "address" portion of the pointer.
+    ///
+    /// This method discards pointer semantic metadata, so the result cannot be
+    /// directly cast into a valid pointer.
+    ///
+    /// Equivalent to calling [`pointer::addr`] on each lane.
+    fn addr(self) -> Self::Usize;
+
+    /// Creates a new pointer with the given address.
+    ///
+    /// This performs the same operation as a cast, but copies the *address-space* and
+    /// *provenance* of `self` to the new pointer.
+    ///
+    /// Equivalent to calling [`pointer::with_addr`] on each lane.
+    fn with_addr(self, addr: Self::Usize) -> Self;
+
+    /// Gets the "address" portion of the pointer, and "exposes" the provenance part for future use
+    /// in [`Self::from_exposed_addr`].
+    fn expose_addr(self) -> Self::Usize;
+
+    /// Convert an address back to a pointer, picking up a previously "exposed" provenance.
+    ///
+    /// Equivalent to calling [`core::ptr::from_exposed_addr_mut`] on each lane.
+    fn from_exposed_addr(addr: Self::Usize) -> Self;
+
+    /// Calculates the offset from a pointer using wrapping arithmetic.
+    ///
+    /// Equivalent to calling [`pointer::wrapping_offset`] on each lane.
+    fn wrapping_offset(self, offset: Self::Isize) -> Self;
+
+    /// Calculates the offset from a pointer using wrapping arithmetic.
+    ///
+    /// Equivalent to calling [`pointer::wrapping_add`] on each lane.
+    fn wrapping_add(self, count: Self::Usize) -> Self;
+
+    /// Calculates the offset from a pointer using wrapping arithmetic.
+    ///
+    /// Equivalent to calling [`pointer::wrapping_sub`] on each lane.
+    fn wrapping_sub(self, count: Self::Usize) -> Self;
+}
+
+impl<T, const LANES: usize> Sealed for Simd<*mut T, LANES> where LaneCount<LANES>: SupportedLaneCount
+{}
+
+impl<T, const LANES: usize> SimdMutPtr for Simd<*mut T, LANES>
+where
+    LaneCount<LANES>: SupportedLaneCount,
+{
+    type Usize = Simd<usize, LANES>;
+    type Isize = Simd<isize, LANES>;
+    type ConstPtr = Simd<*const T, LANES>;
+    type Mask = Mask<isize, LANES>;
+
+    #[inline]
+    fn is_null(self) -> Self::Mask {
+        Simd::splat(core::ptr::null_mut()).simd_eq(self)
+    }
+
+    #[inline]
+    fn cast_const(self) -> Self::ConstPtr {
+        self.cast_ptr()
+    }
+
+    #[inline]
+    fn addr(self) -> Self::Usize {
+        // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic.
+        // SAFETY: Pointer-to-integer transmutes are valid (if you are okay with losing the
+        // provenance).
+        unsafe { core::mem::transmute_copy(&self) }
+    }
+
+    #[inline]
+    fn with_addr(self, addr: Self::Usize) -> Self {
+        // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic.
+        //
+        // In the mean-time, this operation is defined to be "as if" it was
+        // a wrapping_offset, so we can emulate it as such. This should properly
+        // restore pointer provenance even under today's compiler.
+        self.cast_ptr::<*mut u8>()
+            .wrapping_offset(addr.cast::<isize>() - self.addr().cast::<isize>())
+            .cast_ptr()
+    }
+
+    #[inline]
+    fn expose_addr(self) -> Self::Usize {
+        // Safety: `self` is a pointer vector
+        unsafe { intrinsics::simd_expose_addr(self) }
+    }
+
+    #[inline]
+    fn from_exposed_addr(addr: Self::Usize) -> Self {
+        // Safety: `self` is a pointer vector
+        unsafe { intrinsics::simd_from_exposed_addr(addr) }
+    }
+
+    #[inline]
+    fn wrapping_offset(self, count: Self::Isize) -> Self {
+        // Safety: simd_arith_offset takes a vector of pointers and a vector of offsets
+        unsafe { intrinsics::simd_arith_offset(self, count) }
+    }
+
+    #[inline]
+    fn wrapping_add(self, count: Self::Usize) -> Self {
+        self.wrapping_offset(count.cast())
+    }
+
+    #[inline]
+    fn wrapping_sub(self, count: Self::Usize) -> Self {
+        self.wrapping_offset(-count.cast::<isize>())
+    }
+}