Rollup merge of rust-lang#130762 - RalfJung:const_intrinsic_copy, r=dtolnay

stabilize const_intrinsic_copy

Fixes rust-lang#80697

This stabilizes
```rust
mod ptr {
    pub const unsafe fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: usize);
    pub const unsafe fn copy<T>(src: *const T, dst: *mut T, count: usize);
}

impl *const T {
    pub const unsafe fn copy_to(self, dest: *mut T, count: usize);
    pub const unsafe fn copy_to_nonoverlapping(self, dest: *mut T, count: usize);
}

impl *mut T {
    pub const unsafe fn copy_to(self, dest: *mut T, count: usize);
    pub const unsafe fn copy_to_nonoverlapping(self, dest: *mut T, count: usize);

    pub const unsafe fn copy_from(self, src: *const T, count: usize);
    pub const unsafe fn copy_from_nonoverlapping(self, src: *const T, count: usize);
}

impl <T> NonNull<T> {
    pub const unsafe fn copy_to(self, dest: NonNull<T>, count: usize);
    pub const unsafe fn copy_to_nonoverlapping(self, dest: NonNull<T>, count: usize);

    pub const unsafe fn copy_from(self, src: NonNull<T>, count: usize);
    pub const unsafe fn copy_from_nonoverlapping(self, src: NonNull<T>, count: usize);
}
```
In particular, this reverts rust-lang#117905, which reverted rust-lang#97276.

The `NonNull` methods are not listed in the tracking issue, they were added to this feature gate in rust-lang#124498. The existing [FCP](rust-lang#80697 (comment)) does not cover them. They are however entirely identical to the `*mut` methods and already stable outside `const`. ``@rust-lang/libs-api`` please let me know if FCP will be required for the `NonNull` methods.

Author: compiler-errors

core/src/intrinsics.rs

@@ -3286,13 +3286,13 @@ pub const fn ptr_metadata<P: ptr::Pointee<Metadata = M> + ?Sized, M>(_ptr: *cons
 #[doc(alias = "memcpy")]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_allowed_through_unstable_modules]
-#[rustc_const_unstable(feature = "const_intrinsic_copy", issue = "80697")]
+#[rustc_const_stable(feature = "const_intrinsic_copy", since = "CURRENT_RUSTC_VERSION")]
 #[inline(always)]
 #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
 #[rustc_diagnostic_item = "ptr_copy_nonoverlapping"]
 pub const unsafe fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: usize) {
     extern "rust-intrinsic" {
-        #[rustc_const_unstable(feature = "const_intrinsic_copy", issue = "80697")]
+        #[rustc_const_stable(feature = "const_intrinsic_copy", since = "CURRENT_RUSTC_VERSION")]
         #[rustc_nounwind]
         pub fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: usize);
     }
@@ -3388,13 +3388,13 @@ pub const unsafe fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: us
 #[doc(alias = "memmove")]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_allowed_through_unstable_modules]
-#[rustc_const_unstable(feature = "const_intrinsic_copy", issue = "80697")]
+#[rustc_const_stable(feature = "const_intrinsic_copy", since = "CURRENT_RUSTC_VERSION")]
 #[inline(always)]
 #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
 #[rustc_diagnostic_item = "ptr_copy"]
 pub const unsafe fn copy<T>(src: *const T, dst: *mut T, count: usize) {
     extern "rust-intrinsic" {
-        #[rustc_const_unstable(feature = "const_intrinsic_copy", issue = "80697")]
+        #[rustc_const_stable(feature = "const_intrinsic_copy", since = "CURRENT_RUSTC_VERSION")]
         #[rustc_nounwind]
         fn copy<T>(src: *const T, dst: *mut T, count: usize);
     }

core/src/lib.rs

@@ -128,7 +128,6 @@
 #![feature(const_hash)]
 #![feature(const_heap)]
 #![feature(const_index_range_slice_index)]
-#![feature(const_intrinsic_copy)]
 #![feature(const_intrinsic_forget)]
 #![feature(const_ipv4)]
 #![feature(const_ipv6)]

core/src/ptr/const_ptr.rs

@@ -1192,7 +1192,7 @@ impl<T: ?Sized> *const T {
     /// See [`ptr::copy`] for safety concerns and examples.
     ///
     /// [`ptr::copy`]: crate::ptr::copy()
-    #[rustc_const_unstable(feature = "const_intrinsic_copy", issue = "80697")]
+    #[rustc_const_stable(feature = "const_intrinsic_copy", since = "CURRENT_RUSTC_VERSION")]
     #[stable(feature = "pointer_methods", since = "1.26.0")]
     #[inline]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
@@ -1212,7 +1212,7 @@ impl<T: ?Sized> *const T {
     /// See [`ptr::copy_nonoverlapping`] for safety concerns and examples.
     ///
     /// [`ptr::copy_nonoverlapping`]: crate::ptr::copy_nonoverlapping()
-    #[rustc_const_unstable(feature = "const_intrinsic_copy", issue = "80697")]
+    #[rustc_const_stable(feature = "const_intrinsic_copy", since = "CURRENT_RUSTC_VERSION")]
     #[stable(feature = "pointer_methods", since = "1.26.0")]
     #[inline]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces

core/src/ptr/mod.rs

@@ -1516,11 +1516,7 @@ pub const unsafe fn read<T>(src: *const T) -> T {
 #[inline]
 #[stable(feature = "ptr_unaligned", since = "1.17.0")]
 #[rustc_const_stable(feature = "const_ptr_read", since = "1.71.0")]
-#[rustc_allow_const_fn_unstable(
-    const_mut_refs,
-    const_maybe_uninit_as_mut_ptr,
-    const_intrinsic_copy
-)]
+#[cfg_attr(bootstrap, rustc_allow_const_fn_unstable(const_mut_refs))]
 #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
 #[rustc_diagnostic_item = "ptr_read_unaligned"]
 pub const unsafe fn read_unaligned<T>(src: *const T) -> T {

core/src/ptr/mut_ptr.rs

@@ -1269,7 +1269,7 @@ impl<T: ?Sized> *mut T {
     /// See [`ptr::copy`] for safety concerns and examples.
     ///
     /// [`ptr::copy`]: crate::ptr::copy()
-    #[rustc_const_unstable(feature = "const_intrinsic_copy", issue = "80697")]
+    #[rustc_const_stable(feature = "const_intrinsic_copy", since = "CURRENT_RUSTC_VERSION")]
     #[stable(feature = "pointer_methods", since = "1.26.0")]
     #[inline(always)]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
@@ -1289,7 +1289,7 @@ impl<T: ?Sized> *mut T {
     /// See [`ptr::copy_nonoverlapping`] for safety concerns and examples.
     ///
     /// [`ptr::copy_nonoverlapping`]: crate::ptr::copy_nonoverlapping()
-    #[rustc_const_unstable(feature = "const_intrinsic_copy", issue = "80697")]
+    #[rustc_const_stable(feature = "const_intrinsic_copy", since = "CURRENT_RUSTC_VERSION")]
     #[stable(feature = "pointer_methods", since = "1.26.0")]
     #[inline(always)]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
@@ -1309,7 +1309,7 @@ impl<T: ?Sized> *mut T {
     /// See [`ptr::copy`] for safety concerns and examples.
     ///
     /// [`ptr::copy`]: crate::ptr::copy()
-    #[rustc_const_unstable(feature = "const_intrinsic_copy", issue = "80697")]
+    #[rustc_const_stable(feature = "const_intrinsic_copy", since = "CURRENT_RUSTC_VERSION")]
     #[stable(feature = "pointer_methods", since = "1.26.0")]
     #[inline(always)]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
@@ -1329,7 +1329,7 @@ impl<T: ?Sized> *mut T {
     /// See [`ptr::copy_nonoverlapping`] for safety concerns and examples.
     ///
     /// [`ptr::copy_nonoverlapping`]: crate::ptr::copy_nonoverlapping()
-    #[rustc_const_unstable(feature = "const_intrinsic_copy", issue = "80697")]
+    #[rustc_const_stable(feature = "const_intrinsic_copy", since = "CURRENT_RUSTC_VERSION")]
     #[stable(feature = "pointer_methods", since = "1.26.0")]
     #[inline(always)]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces

core/src/ptr/non_null.rs

@@ -924,7 +924,7 @@ impl<T: ?Sized> NonNull<T> {
     #[inline(always)]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
     #[stable(feature = "non_null_convenience", since = "1.80.0")]
-    #[rustc_const_unstable(feature = "const_intrinsic_copy", issue = "80697")]
+    #[rustc_const_stable(feature = "const_intrinsic_copy", since = "CURRENT_RUSTC_VERSION")]
     pub const unsafe fn copy_to(self, dest: NonNull<T>, count: usize)
     where
         T: Sized,
@@ -944,7 +944,7 @@ impl<T: ?Sized> NonNull<T> {
     #[inline(always)]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
     #[stable(feature = "non_null_convenience", since = "1.80.0")]
-    #[rustc_const_unstable(feature = "const_intrinsic_copy", issue = "80697")]
+    #[rustc_const_stable(feature = "const_intrinsic_copy", since = "CURRENT_RUSTC_VERSION")]
     pub const unsafe fn copy_to_nonoverlapping(self, dest: NonNull<T>, count: usize)
     where
         T: Sized,
@@ -964,7 +964,7 @@ impl<T: ?Sized> NonNull<T> {
     #[inline(always)]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
     #[stable(feature = "non_null_convenience", since = "1.80.0")]
-    #[rustc_const_unstable(feature = "const_intrinsic_copy", issue = "80697")]
+    #[rustc_const_stable(feature = "const_intrinsic_copy", since = "CURRENT_RUSTC_VERSION")]
     pub const unsafe fn copy_from(self, src: NonNull<T>, count: usize)
     where
         T: Sized,
@@ -984,7 +984,7 @@ impl<T: ?Sized> NonNull<T> {
     #[inline(always)]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
     #[stable(feature = "non_null_convenience", since = "1.80.0")]
-    #[rustc_const_unstable(feature = "const_intrinsic_copy", issue = "80697")]
+    #[rustc_const_stable(feature = "const_intrinsic_copy", since = "CURRENT_RUSTC_VERSION")]
     pub const unsafe fn copy_from_nonoverlapping(self, src: NonNull<T>, count: usize)
     where
         T: Sized,

core/tests/lib.rs

@@ -21,7 +21,6 @@
 #![feature(const_cell_into_inner)]
 #![feature(const_hash)]
 #![feature(const_heap)]
-#![feature(const_intrinsic_copy)]
 #![feature(const_ip)]
 #![feature(const_ipv4)]
 #![feature(const_ipv6)]

portable-simd/crates/core_simd/src/lib.rs

@@ -1,8 +1,6 @@
 #![no_std]
 #![feature(
-    const_intrinsic_copy,
     const_refs_to_cell,
-    const_maybe_uninit_as_mut_ptr,
     const_mut_refs,
     convert_float_to_int,
     core_intrinsics,