Merge ref '125ff8a788c5' from rust-lang/rust

Pull recent changes from https://github.com/rust-lang/rust via Josh.

Upstream ref: 125ff8a
Filtered ref: bcbe2eb9c674ba7e35befb4557f33a1956964256

This merge was created using https://github.com/rust-lang/josh-sync.

Author: The Miri Cronjob Bot

Cargo.lock

@@ -59,4 +59,3 @@ rustflags = ["-Cpanic=abort"]
 rustc-std-workspace-core = { path = 'rustc-std-workspace-core' }
 rustc-std-workspace-alloc = { path = 'rustc-std-workspace-alloc' }
 rustc-std-workspace-std = { path = 'rustc-std-workspace-std' }
-compiler_builtins = { path = "compiler-builtins/compiler-builtins" }

Cargo.toml

@@ -17,6 +17,7 @@ unsafe extern "Rust" {
     #[rustc_allocator]
     #[rustc_nounwind]
     #[rustc_std_internal_symbol]
+    #[rustc_allocator_zeroed_variant = "__rust_alloc_zeroed"]
     fn __rust_alloc(size: usize, align: usize) -> *mut u8;
     #[rustc_deallocator]
     #[rustc_nounwind]

alloc/src/alloc.rs

@@ -1554,6 +1554,9 @@ pub fn min<T: Ord>(v1: T, v2: T) -> T {
 ///
 /// Returns the first argument if the comparison determines them to be equal.
 ///
+/// The parameter order is preserved when calling the `compare` function, i.e. `v1` is
+/// always passed as the first argument and `v2` as the second.
+///
 /// # Examples
 ///
 /// ```
@@ -1574,7 +1577,7 @@ pub fn min<T: Ord>(v1: T, v2: T) -> T {
 #[must_use]
 #[stable(feature = "cmp_min_max_by", since = "1.53.0")]
 pub fn min_by<T, F: FnOnce(&T, &T) -> Ordering>(v1: T, v2: T, compare: F) -> T {
-    if compare(&v2, &v1).is_lt() { v2 } else { v1 }
+    if compare(&v1, &v2).is_le() { v1 } else { v2 }
 }
 
 /// Returns the element that gives the minimum value from the specified function.
@@ -1646,6 +1649,9 @@ pub fn max<T: Ord>(v1: T, v2: T) -> T {
 ///
 /// Returns the second argument if the comparison determines them to be equal.
 ///
+/// The parameter order is preserved when calling the `compare` function, i.e. `v1` is
+/// always passed as the first argument and `v2` as the second.
+///
 /// # Examples
 ///
 /// ```
@@ -1666,7 +1672,7 @@ pub fn max<T: Ord>(v1: T, v2: T) -> T {
 #[must_use]
 #[stable(feature = "cmp_min_max_by", since = "1.53.0")]
 pub fn max_by<T, F: FnOnce(&T, &T) -> Ordering>(v1: T, v2: T, compare: F) -> T {
-    if compare(&v2, &v1).is_lt() { v1 } else { v2 }
+    if compare(&v1, &v2).is_gt() { v1 } else { v2 }
 }
 
 /// Returns the element that gives the maximum value from the specified function.
@@ -1745,6 +1751,9 @@ where
 ///
 /// Returns `[v1, v2]` if the comparison determines them to be equal.
 ///
+/// The parameter order is preserved when calling the `compare` function, i.e. `v1` is
+/// always passed as the first argument and `v2` as the second.
+///
 /// # Examples
 ///
 /// ```
@@ -1769,7 +1778,7 @@ pub fn minmax_by<T, F>(v1: T, v2: T, compare: F) -> [T; 2]
 where
     F: FnOnce(&T, &T) -> Ordering,
 {
-    if compare(&v2, &v1).is_lt() { [v2, v1] } else { [v1, v2] }
+    if compare(&v1, &v2).is_le() { [v1, v2] } else { [v2, v1] }
 }
 
 /// Returns minimum and maximum values with respect to the specified key function.

core/src/cmp.rs

@@ -261,53 +261,72 @@ pub unsafe fn atomic_fence<const ORD: AtomicOrdering>();
 pub unsafe fn atomic_singlethreadfence<const ORD: AtomicOrdering>();
 
 /// The `prefetch` intrinsic is a hint to the code generator to insert a prefetch instruction
-/// if supported; otherwise, it is a no-op.
+/// for the given address if supported; otherwise, it is a no-op.
 /// Prefetches have no effect on the behavior of the program but can change its performance
 /// characteristics.
 ///
-/// The `locality` argument must be a constant integer and is a temporal locality specifier
-/// ranging from (0) - no locality, to (3) - extremely local keep in cache.
+/// The `LOCALITY` argument is a temporal locality specifier ranging from (0) - no locality,
+/// to (3) - extremely local keep in cache.
 ///
 /// This intrinsic does not have a stable counterpart.
 #[rustc_intrinsic]
 #[rustc_nounwind]
-pub unsafe fn prefetch_read_data<T>(data: *const T, locality: i32);
+#[miri::intrinsic_fallback_is_spec]
+pub const fn prefetch_read_data<T, const LOCALITY: i32>(data: *const T) {
+    // This operation is a no-op, unless it is overridden by the backend.
+    let _ = data;
+}
+
 /// The `prefetch` intrinsic is a hint to the code generator to insert a prefetch instruction
-/// if supported; otherwise, it is a no-op.
+/// for the given address if supported; otherwise, it is a no-op.
 /// Prefetches have no effect on the behavior of the program but can change its performance
 /// characteristics.
 ///
-/// The `locality` argument must be a constant integer and is a temporal locality specifier
-/// ranging from (0) - no locality, to (3) - extremely local keep in cache.
+/// The `LOCALITY` argument is a temporal locality specifier ranging from (0) - no locality,
+/// to (3) - extremely local keep in cache.
 ///
 /// This intrinsic does not have a stable counterpart.
 #[rustc_intrinsic]
 #[rustc_nounwind]
-pub unsafe fn prefetch_write_data<T>(data: *const T, locality: i32);
+#[miri::intrinsic_fallback_is_spec]
+pub const fn prefetch_write_data<T, const LOCALITY: i32>(data: *const T) {
+    // This operation is a no-op, unless it is overridden by the backend.
+    let _ = data;
+}
+
 /// The `prefetch` intrinsic is a hint to the code generator to insert a prefetch instruction
-/// if supported; otherwise, it is a no-op.
+/// for the given address if supported; otherwise, it is a no-op.
 /// Prefetches have no effect on the behavior of the program but can change its performance
 /// characteristics.
 ///
-/// The `locality` argument must be a constant integer and is a temporal locality specifier
-/// ranging from (0) - no locality, to (3) - extremely local keep in cache.
+/// The `LOCALITY` argument is a temporal locality specifier ranging from (0) - no locality,
+/// to (3) - extremely local keep in cache.
 ///
 /// This intrinsic does not have a stable counterpart.
 #[rustc_intrinsic]
 #[rustc_nounwind]
-pub unsafe fn prefetch_read_instruction<T>(data: *const T, locality: i32);
+#[miri::intrinsic_fallback_is_spec]
+pub const fn prefetch_read_instruction<T, const LOCALITY: i32>(data: *const T) {
+    // This operation is a no-op, unless it is overridden by the backend.
+    let _ = data;
+}
+
 /// The `prefetch` intrinsic is a hint to the code generator to insert a prefetch instruction
-/// if supported; otherwise, it is a no-op.
+/// for the given address if supported; otherwise, it is a no-op.
 /// Prefetches have no effect on the behavior of the program but can change its performance
 /// characteristics.
 ///
-/// The `locality` argument must be a constant integer and is a temporal locality specifier
-/// ranging from (0) - no locality, to (3) - extremely local keep in cache.
+/// The `LOCALITY` argument is a temporal locality specifier ranging from (0) - no locality,
+/// to (3) - extremely local keep in cache.
 ///
 /// This intrinsic does not have a stable counterpart.
 #[rustc_intrinsic]
 #[rustc_nounwind]
-pub unsafe fn prefetch_write_instruction<T>(data: *const T, locality: i32);
+#[miri::intrinsic_fallback_is_spec]
+pub const fn prefetch_write_instruction<T, const LOCALITY: i32>(data: *const T) {
+    // This operation is a no-op, unless it is overridden by the backend.
+    let _ = data;
+}
 
 /// Executes a breakpoint trap, for inspection by a debugger.
 ///

core/src/intrinsics/mod.rs

@@ -209,6 +209,48 @@ macro_rules! int_impl {
             self & self.wrapping_neg()
         }
 
+        /// Returns the index of the highest bit set to one in `self`, or `None`
+        /// if `self` is `0`.
+        ///
+        /// # Examples
+        ///
+        /// ```
+        /// #![feature(int_lowest_highest_one)]
+        ///
+        #[doc = concat!("assert_eq!(0x0_", stringify!($SelfT), ".highest_one(), None);")]
+        #[doc = concat!("assert_eq!(0x1_", stringify!($SelfT), ".highest_one(), Some(0));")]
+        #[doc = concat!("assert_eq!(0x10_", stringify!($SelfT), ".highest_one(), Some(4));")]
+        #[doc = concat!("assert_eq!(0x1f_", stringify!($SelfT), ".highest_one(), Some(4));")]
+        /// ```
+        #[unstable(feature = "int_lowest_highest_one", issue = "145203")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline(always)]
+        pub const fn highest_one(self) -> Option<u32> {
+            (self as $UnsignedT).highest_one()
+        }
+
+        /// Returns the index of the lowest bit set to one in `self`, or `None`
+        /// if `self` is `0`.
+        ///
+        /// # Examples
+        ///
+        /// ```
+        /// #![feature(int_lowest_highest_one)]
+        ///
+        #[doc = concat!("assert_eq!(0x0_", stringify!($SelfT), ".lowest_one(), None);")]
+        #[doc = concat!("assert_eq!(0x1_", stringify!($SelfT), ".lowest_one(), Some(0));")]
+        #[doc = concat!("assert_eq!(0x10_", stringify!($SelfT), ".lowest_one(), Some(4));")]
+        #[doc = concat!("assert_eq!(0x1f_", stringify!($SelfT), ".lowest_one(), Some(0));")]
+        /// ```
+        #[unstable(feature = "int_lowest_highest_one", issue = "145203")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline(always)]
+        pub const fn lowest_one(self) -> Option<u32> {
+            (self as $UnsignedT).lowest_one()
+        }
+
         /// Returns the bit pattern of `self` reinterpreted as an unsigned integer of the same size.
         ///
         /// This produces the same result as an `as` cast, but ensures that the bit-width remains

core/src/num/int_macros.rs

@@ -681,6 +681,54 @@ macro_rules! nonzero_integer {
                 unsafe { NonZero::new_unchecked(n) }
             }
 
+            /// Returns the index of the highest bit set to one in `self`.
+            ///
+            /// # Examples
+            ///
+            /// ```
+            /// #![feature(int_lowest_highest_one)]
+            ///
+            /// # use core::num::NonZero;
+            /// # fn main() { test().unwrap(); }
+            /// # fn test() -> Option<()> {
+            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0x1)?.highest_one(), 0);")]
+            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0x10)?.highest_one(), 4);")]
+            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0x1f)?.highest_one(), 4);")]
+            /// # Some(())
+            /// # }
+            /// ```
+            #[unstable(feature = "int_lowest_highest_one", issue = "145203")]
+            #[must_use = "this returns the result of the operation, \
+                          without modifying the original"]
+            #[inline(always)]
+            pub const fn highest_one(self) -> u32 {
+                Self::BITS - 1 - self.leading_zeros()
+            }
+
+            /// Returns the index of the lowest bit set to one in `self`.
+            ///
+            /// # Examples
+            ///
+            /// ```
+            /// #![feature(int_lowest_highest_one)]
+            ///
+            /// # use core::num::NonZero;
+            /// # fn main() { test().unwrap(); }
+            /// # fn test() -> Option<()> {
+            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0x1)?.lowest_one(), 0);")]
+            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0x10)?.lowest_one(), 4);")]
+            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0x1f)?.lowest_one(), 0);")]
+            /// # Some(())
+            /// # }
+            /// ```
+            #[unstable(feature = "int_lowest_highest_one", issue = "145203")]
+            #[must_use = "this returns the result of the operation, \
+                          without modifying the original"]
+            #[inline(always)]
+            pub const fn lowest_one(self) -> u32 {
+                self.trailing_zeros()
+            }
+
             /// Returns the number of ones in the binary representation of `self`.
             ///
             /// # Examples

core/src/num/nonzero.rs

@@ -261,6 +261,54 @@ macro_rules! uint_impl {
             self & self.wrapping_neg()
         }
 
+        /// Returns the index of the highest bit set to one in `self`, or `None`
+        /// if `self` is `0`.
+        ///
+        /// # Examples
+        ///
+        /// ```
+        /// #![feature(int_lowest_highest_one)]
+        ///
+        #[doc = concat!("assert_eq!(0x0_", stringify!($SelfT), ".highest_one(), None);")]
+        #[doc = concat!("assert_eq!(0x1_", stringify!($SelfT), ".highest_one(), Some(0));")]
+        #[doc = concat!("assert_eq!(0x10_", stringify!($SelfT), ".highest_one(), Some(4));")]
+        #[doc = concat!("assert_eq!(0x1f_", stringify!($SelfT), ".highest_one(), Some(4));")]
+        /// ```
+        #[unstable(feature = "int_lowest_highest_one", issue = "145203")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline(always)]
+        pub const fn highest_one(self) -> Option<u32> {
+            match NonZero::new(self) {
+                Some(v) => Some(v.highest_one()),
+                None => None,
+            }
+        }
+
+        /// Returns the index of the lowest bit set to one in `self`, or `None`
+        /// if `self` is `0`.
+        ///
+        /// # Examples
+        ///
+        /// ```
+        /// #![feature(int_lowest_highest_one)]
+        ///
+        #[doc = concat!("assert_eq!(0x0_", stringify!($SelfT), ".lowest_one(), None);")]
+        #[doc = concat!("assert_eq!(0x1_", stringify!($SelfT), ".lowest_one(), Some(0));")]
+        #[doc = concat!("assert_eq!(0x10_", stringify!($SelfT), ".lowest_one(), Some(4));")]
+        #[doc = concat!("assert_eq!(0x1f_", stringify!($SelfT), ".lowest_one(), Some(0));")]
+        /// ```
+        #[unstable(feature = "int_lowest_highest_one", issue = "145203")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline(always)]
+        pub const fn lowest_one(self) -> Option<u32> {
+            match NonZero::new(self) {
+                Some(v) => Some(v.lowest_one()),
+                None => None,
+            }
+        }
+
         /// Returns the bit pattern of `self` reinterpreted as a signed integer of the same size.
         ///
         /// This produces the same result as an `as` cast, but ensures that the bit-width remains

core/src/num/uint_macros.rs

@@ -54,6 +54,7 @@
 #![feature(generic_assert_internals)]
 #![feature(hasher_prefixfree_extras)]
 #![feature(hashmap_internals)]
+#![feature(int_lowest_highest_one)]
 #![feature(int_roundings)]
 #![feature(ip)]
 #![feature(is_ascii_octdigit)]