Auto merge of #135789 - matthiaskrgr:rollup-4cvw8s4, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - #133695 (Reexport likely/unlikely in std::hint)
 - #135330 (Respect --sysroot for rustc -vV and -Cpasses=list)
 - #135333 (Partial progress on #132735: Replace extern "rust-intrinsic" with #[rustc_intrinsic] across the codebase)
 - #135741 (Recognise new IPv6 documentation range from IETF RFC 9637)
 - #135770 (Update contributing docs for submodule/subtree changes)
 - #135775 (Subtree update of `rust-analyzer`)
 - #135776 (Subtree sync for rustc_codegen_cranelift)

r? `@ghost`
`@rustbot` modify labels: rollup

3 files changed, 152 insertions, 4 deletions

diff --git a/library/core/src/hint.rs b/library/core/src/hint.rs
index 9c054b99a27..80f6e32b6b2 100644
--- a/library/core/src/hint.rs
+++ b/library/core/src/hint.rs
@@ -597,3 +597,138 @@ pub const fn black_box<T>(dummy: T) -> T {
 pub const fn must_use<T>(value: T) -> T {
     value
 }
+
+/// Hints to the compiler that a branch condition is likely to be true.
+/// Returns the value passed to it.
+///
+/// It can be used with `if` or boolean `match` expressions.
+///
+/// When used outside of a branch condition, it may still influence a nearby branch, but
+/// probably will not have any effect.
+///
+/// It can also be applied to parts of expressions, such as `likely(a) && unlikely(b)`, or to
+/// compound expressions, such as `likely(a && b)`. When applied to compound expressions, it has
+/// the following effect:
+/// ```text
+///     likely(!a) => !unlikely(a)
+///     likely(a && b) => likely(a) && likely(b)
+///     likely(a || b) => a || likely(b)
+/// ```
+///
+/// See also the function [`cold_path()`] which may be more appropriate for idiomatic Rust code.
+///
+/// # Examples
+///
+/// ```
+/// #![feature(likely_unlikely)]
+/// use core::hint::likely;
+///
+/// fn foo(x: i32) {
+///     if likely(x > 0) {
+///         println!("this branch is likely to be taken");
+///     } else {
+///         println!("this branch is unlikely to be taken");
+///     }
+///
+///     match likely(x > 0) {
+///         true => println!("this branch is likely to be taken"),
+///         false => println!("this branch is unlikely to be taken"),
+///     }
+///
+///     // Use outside of a branch condition may still influence a nearby branch
+///     let cond = likely(x != 0);
+///     if cond {
+///         println!("this branch is likely to be taken");
+///     }
+/// }
+/// ```
+///
+///
+#[unstable(feature = "likely_unlikely", issue = "26179")]
+#[inline(always)]
+pub const fn likely(b: bool) -> bool {
+    crate::intrinsics::likely(b)
+}
+
+/// Hints to the compiler that a branch condition is unlikely to be true.
+/// Returns the value passed to it.
+///
+/// It can be used with `if` or boolean `match` expressions.
+///
+/// When used outside of a branch condition, it may still influence a nearby branch, but
+/// probably will not have any effect.
+///
+/// It can also be applied to parts of expressions, such as `likely(a) && unlikely(b)`, or to
+/// compound expressions, such as `unlikely(a && b)`. When applied to compound expressions, it has
+/// the following effect:
+/// ```text
+///     unlikely(!a) => !likely(a)
+///     unlikely(a && b) => a && unlikely(b)
+///     unlikely(a || b) => unlikely(a) || unlikely(b)
+/// ```
+///
+/// See also the function [`cold_path()`] which may be more appropriate for idiomatic Rust code.
+///
+/// # Examples
+///
+/// ```
+/// #![feature(likely_unlikely)]
+/// use core::hint::unlikely;
+///
+/// fn foo(x: i32) {
+///     if unlikely(x > 0) {
+///         println!("this branch is unlikely to be taken");
+///     } else {
+///         println!("this branch is likely to be taken");
+///     }
+///
+///     match unlikely(x > 0) {
+///         true => println!("this branch is unlikely to be taken"),
+///         false => println!("this branch is likely to be taken"),
+///     }
+///
+///     // Use outside of a branch condition may still influence a nearby branch
+///     let cond = unlikely(x != 0);
+///     if cond {
+///         println!("this branch is likely to be taken");
+///     }
+/// }
+/// ```
+#[unstable(feature = "likely_unlikely", issue = "26179")]
+#[inline(always)]
+pub const fn unlikely(b: bool) -> bool {
+    crate::intrinsics::unlikely(b)
+}
+
+/// Hints to the compiler that given path is cold, i.e., unlikely to be taken. The compiler may
+/// choose to optimize paths that are not cold at the expense of paths that are cold.
+///
+/// # Examples
+///
+/// ```
+/// #![feature(cold_path)]
+/// use core::hint::cold_path;
+///
+/// fn foo(x: &[i32]) {
+///     if let Some(first) = x.get(0) {
+///         // this is the fast path
+///     } else {
+///         // this path is unlikely
+///         cold_path();
+///     }
+/// }
+///
+/// fn bar(x: i32) -> i32 {
+///     match x {
+///         1 => 10,
+///         2 => 100,
+///         3 => { cold_path(); 1000 }, // this branch is unlikely
+///         _ => { cold_path(); 10000 }, // this is also unlikely
+///     }
+/// }
+/// ```
+#[unstable(feature = "cold_path", issue = "26179")]
+#[inline(always)]
+pub const fn cold_path() {
+    crate::intrinsics::cold_path()
+}
diff --git a/library/core/src/net/ip_addr.rs b/library/core/src/net/ip_addr.rs
index 7dd5c214012..b11ba056853 100644
--- a/library/core/src/net/ip_addr.rs
+++ b/library/core/src/net/ip_addr.rs
@@ -1539,8 +1539,9 @@ impl Ipv6Addr {
     /// // Addresses reserved for benchmarking (`2001:2::/48`)
     /// assert_eq!(Ipv6Addr::new(0x2001, 2, 0, 0, 0, 0, 0, 1,).is_global(), false);
     ///
-    /// // Addresses reserved for documentation (`2001:db8::/32`)
+    /// // Addresses reserved for documentation (`2001:db8::/32` and `3fff::/20`)
     /// assert_eq!(Ipv6Addr::new(0x2001, 0xdb8, 0, 0, 0, 0, 0, 1).is_global(), false);
+    /// assert_eq!(Ipv6Addr::new(0x3fff, 0, 0, 0, 0, 0, 0, 0).is_global(), false);
     ///
     /// // Unique local addresses (`fc00::/7`)
     /// assert_eq!(Ipv6Addr::new(0xfc02, 0, 0, 0, 0, 0, 0, 1).is_global(), false);
@@ -1686,11 +1687,12 @@ impl Ipv6Addr {
     }
 
     /// Returns [`true`] if this is an address reserved for documentation
-    /// (`2001:db8::/32`).
+    /// (`2001:db8::/32` and `3fff::/20`).
     ///
-    /// This property is defined in [IETF RFC 3849].
+    /// This property is defined by [IETF RFC 3849] and [IETF RFC 9637].
     ///
     /// [IETF RFC 3849]: https://tools.ietf.org/html/rfc3849
+    /// [IETF RFC 9637]: https://tools.ietf.org/html/rfc9637
     ///
     /// # Examples
     ///
@@ -1701,12 +1703,13 @@ impl Ipv6Addr {
     ///
     /// assert_eq!(Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff, 0xc00a, 0x2ff).is_documentation(), false);
     /// assert_eq!(Ipv6Addr::new(0x2001, 0xdb8, 0, 0, 0, 0, 0, 0).is_documentation(), true);
+    /// assert_eq!(Ipv6Addr::new(0x3fff, 0, 0, 0, 0, 0, 0, 0).is_documentation(), true);
     /// ```
     #[unstable(feature = "ip", issue = "27709")]
     #[must_use]
     #[inline]
     pub const fn is_documentation(&self) -> bool {
-        (self.segments()[0] == 0x2001) && (self.segments()[1] == 0xdb8)
+        matches!(self.segments(), [0x2001, 0xdb8, ..] | [0x3fff, 0..=0x0fff, ..])
     }
 
     /// Returns [`true`] if this is an address reserved for benchmarking (`2001:2::/48`).
diff --git a/library/core/tests/net/ip_addr.rs b/library/core/tests/net/ip_addr.rs
index 707f9a160e1..f01b43282ec 100644
--- a/library/core/tests/net/ip_addr.rs
+++ b/library/core/tests/net/ip_addr.rs
@@ -332,6 +332,7 @@ fn ip_properties() {
     check!("ff08::", global | multicast);
     check!("ff0e::", global | multicast);
     check!("2001:db8:85a3::8a2e:370:7334", doc);
+    check!("3fff:fff:ffff:ffff:ffff:ffff:ffff:ffff", doc);
     check!("2001:2::ac32:23ff:21", benchmarking);
     check!("102:304:506:708:90a:b0c:d0e:f10", global);
 }
@@ -791,6 +792,15 @@ fn ipv6_properties() {
     );
 
     check!(
+        "3fff:fff:ffff:ffff:ffff:ffff:ffff:ffff",
+        &[
+            0x3f, 0xff, 0x0f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+            0xff, 0xff
+        ],
+        documentation
+    );
+
+    check!(
         "2001:2::ac32:23ff:21",
         &[0x20, 1, 0, 2, 0, 0, 0, 0, 0, 0, 0xac, 0x32, 0x23, 0xff, 0, 0x21],
         benchmarking