Auto merge of rust-lang#105262 - eduardosm:more-inline-always, r=thomcc

Make some trivial functions `#[inline(always)]`

This is some kind of follow-up of PRs like rust-lang#85218, rust-lang#84061, rust-lang#87150. Functions that do very basic operations are made `#[inline(always)]` to avoid pessimizing them in debug builds when compared to using built-in operations directly.

library/core/src/clone.rs

@@ -176,7 +176,6 @@ pub struct AssertParamIsCopy<T: Copy + ?Sized> {
 /// are implemented in `traits::SelectionContext::copy_clone_conditions()`
 /// in `rustc_trait_selection`.
 mod impls {
-
     use super::Clone;
 
     macro_rules! impl_clone {
@@ -185,7 +184,7 @@ mod impls {
                 #[stable(feature = "rust1", since = "1.0.0")]
                 #[rustc_const_unstable(feature = "const_clone", issue = "91805")]
                 impl const Clone for $t {
-                    #[inline]
+                    #[inline(always)]
                     fn clone(&self) -> Self {
                         *self
                     }
@@ -213,7 +212,7 @@ mod impls {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature = "const_clone", issue = "91805")]
     impl<T: ?Sized> const Clone for *const T {
-        #[inline]
+        #[inline(always)]
         fn clone(&self) -> Self {
             *self
         }
@@ -222,7 +221,7 @@ mod impls {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature = "const_clone", issue = "91805")]
     impl<T: ?Sized> const Clone for *mut T {
-        #[inline]
+        #[inline(always)]
         fn clone(&self) -> Self {
             *self
         }
@@ -232,7 +231,7 @@ mod impls {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature = "const_clone", issue = "91805")]
     impl<T: ?Sized> const Clone for &T {
-        #[inline]
+        #[inline(always)]
         #[rustc_diagnostic_item = "noop_method_clone"]
         fn clone(&self) -> Self {
             *self

library/core/src/convert/mod.rs

@@ -99,7 +99,7 @@ pub use num::FloatToInt;
 /// ```
 #[stable(feature = "convert_id", since = "1.33.0")]
 #[rustc_const_stable(feature = "const_identity", since = "1.33.0")]
-#[inline]
+#[inline(always)]
 pub const fn identity<T>(x: T) -> T {
     x
 }
@@ -789,29 +789,31 @@ where
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T> AsRef<[T]> for [T] {
+    #[inline(always)]
     fn as_ref(&self) -> &[T] {
         self
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T> AsMut<[T]> for [T] {
+    #[inline(always)]
     fn as_mut(&mut self) -> &mut [T] {
         self
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl AsRef<str> for str {
-    #[inline]
+    #[inline(always)]
     fn as_ref(&self) -> &str {
         self
     }
 }
 
 #[stable(feature = "as_mut_str_for_str", since = "1.51.0")]
 impl AsMut<str> for str {
-    #[inline]
+    #[inline(always)]
     fn as_mut(&mut self) -> &mut str {
         self
     }

library/core/src/hint.rs

@@ -160,7 +160,7 @@ pub const unsafe fn unreachable_unchecked() -> ! {
 /// ```
 ///
 /// [`thread::yield_now`]: ../../std/thread/fn.yield_now.html
-#[inline]
+#[inline(always)]
 #[stable(feature = "renamed_spin_loop", since = "1.49.0")]
 pub fn spin_loop() {
     #[cfg(target_arch = "x86")]
@@ -345,6 +345,7 @@ pub const fn black_box<T>(dummy: T) -> T {
 #[unstable(feature = "hint_must_use", issue = "94745")]
 #[rustc_const_unstable(feature = "hint_must_use", issue = "94745")]
 #[must_use] // <-- :)
+#[inline(always)]
 pub const fn must_use<T>(value: T) -> T {
     value
 }

library/core/src/ptr/const_ptr.rs

@@ -45,7 +45,7 @@ impl<T: ?Sized> *const T {
     /// Casts to a pointer of another type.
     #[stable(feature = "ptr_cast", since = "1.38.0")]
     #[rustc_const_stable(feature = "const_ptr_cast", since = "1.38.0")]
-    #[inline]
+    #[inline(always)]
     pub const fn cast<U>(self) -> *const U {
         self as _
     }
@@ -95,6 +95,7 @@ impl<T: ?Sized> *const T {
     /// refactored.
     #[stable(feature = "ptr_const_cast", since = "1.65.0")]
     #[rustc_const_stable(feature = "ptr_const_cast", since = "1.65.0")]
+    #[inline(always)]
     pub const fn cast_mut(self) -> *mut T {
         self as _
     }
@@ -126,6 +127,7 @@ impl<T: ?Sized> *const T {
         note = "replaced by the `exposed_addr` method, or update your code \
             to follow the strict provenance rules using its APIs"
     )]
+    #[inline(always)]
     pub fn to_bits(self) -> usize
     where
         T: Sized,
@@ -155,6 +157,7 @@ impl<T: ?Sized> *const T {
             your code to follow the strict provenance rules using its APIs"
     )]
     #[allow(fuzzy_provenance_casts)] // this is an unstable and semi-deprecated cast function
+    #[inline(always)]
     pub fn from_bits(bits: usize) -> Self
     where
         T: Sized,
@@ -186,7 +189,7 @@ impl<T: ?Sized> *const T {
     /// might change in the future (including possibly weakening this so it becomes wholly
     /// equivalent to `self as usize`). See the [module documentation][crate::ptr] for details.
     #[must_use]
-    #[inline]
+    #[inline(always)]
     #[unstable(feature = "strict_provenance", issue = "95228")]
     pub fn addr(self) -> usize
     where
@@ -223,7 +226,7 @@ impl<T: ?Sized> *const T {
     ///
     /// [`from_exposed_addr`]: from_exposed_addr
     #[must_use]
-    #[inline]
+    #[inline(always)]
     #[unstable(feature = "strict_provenance", issue = "95228")]
     pub fn expose_addr(self) -> usize
     where

library/core/src/ptr/mod.rs

@@ -613,7 +613,7 @@ pub const fn invalid_mut<T>(addr: usize) -> *mut T {
 /// This API and its claimed semantics are part of the Strict Provenance experiment, see the
 /// [module documentation][crate::ptr] for details.
 #[must_use]
-#[inline]
+#[inline(always)]
 #[unstable(feature = "strict_provenance", issue = "95228")]
 #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
 #[allow(fuzzy_provenance_casts)] // this *is* the strict provenance API one should use instead
@@ -651,7 +651,7 @@ where
 /// This API and its claimed semantics are part of the Strict Provenance experiment, see the
 /// [module documentation][crate::ptr] for details.
 #[must_use]
-#[inline]
+#[inline(always)]
 #[unstable(feature = "strict_provenance", issue = "95228")]
 #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
 #[allow(fuzzy_provenance_casts)] // this *is* the strict provenance API one should use instead
@@ -1801,7 +1801,7 @@ pub(crate) const unsafe fn align_offset<T: Sized>(p: *const T, a: usize) -> usiz
 /// assert!(!std::ptr::eq(&a[0..2], &a[1..3]));
 /// ```
 #[stable(feature = "ptr_eq", since = "1.17.0")]
-#[inline]
+#[inline(always)]
 pub fn eq<T: ?Sized>(a: *const T, b: *const T) -> bool {
     a == b
 }

library/core/src/ptr/mut_ptr.rs

@@ -100,6 +100,7 @@ impl<T: ?Sized> *mut T {
     /// [`cast_mut`]: #method.cast_mut
     #[stable(feature = "ptr_const_cast", since = "1.65.0")]
     #[rustc_const_stable(feature = "ptr_const_cast", since = "1.65.0")]
+    #[inline(always)]
     pub const fn cast_const(self) -> *const T {
         self as _
     }
@@ -132,6 +133,7 @@ impl<T: ?Sized> *mut T {
         note = "replaced by the `exposed_addr` method, or update your code \
             to follow the strict provenance rules using its APIs"
     )]
+    #[inline(always)]
     pub fn to_bits(self) -> usize
     where
         T: Sized,
@@ -161,6 +163,7 @@ impl<T: ?Sized> *mut T {
             update your code to follow the strict provenance rules using its APIs"
     )]
     #[allow(fuzzy_provenance_casts)] // this is an unstable and semi-deprecated cast function
+    #[inline(always)]
     pub fn from_bits(bits: usize) -> Self
     where
         T: Sized,
@@ -192,7 +195,7 @@ impl<T: ?Sized> *mut T {
     /// might change in the future (including possibly weakening this so it becomes wholly
     /// equivalent to `self as usize`). See the [module documentation][crate::ptr] for details.
     #[must_use]
-    #[inline]
+    #[inline(always)]
     #[unstable(feature = "strict_provenance", issue = "95228")]
     pub fn addr(self) -> usize
     where
@@ -229,7 +232,7 @@ impl<T: ?Sized> *mut T {
     ///
     /// [`from_exposed_addr_mut`]: from_exposed_addr_mut
     #[must_use]
-    #[inline]
+    #[inline(always)]
     #[unstable(feature = "strict_provenance", issue = "95228")]
     pub fn expose_addr(self) -> usize
     where

library/core/src/ptr/non_null.rs

@@ -330,7 +330,7 @@ impl<T: ?Sized> NonNull<T> {
     #[stable(feature = "nonnull", since = "1.25.0")]
     #[rustc_const_stable(feature = "const_nonnull_as_ptr", since = "1.32.0")]
     #[must_use]
-    #[inline]
+    #[inline(always)]
     pub const fn as_ptr(self) -> *mut T {
         self.pointer as *mut T
     }
@@ -378,7 +378,7 @@ impl<T: ?Sized> NonNull<T> {
     #[stable(feature = "nonnull", since = "1.25.0")]
     #[rustc_const_unstable(feature = "const_ptr_as_ref", issue = "91822")]
     #[must_use]
-    #[inline]
+    #[inline(always)]
     pub const unsafe fn as_ref<'a>(&self) -> &'a T {
         // SAFETY: the caller must guarantee that `self` meets all the
         // requirements for a reference.
@@ -429,7 +429,7 @@ impl<T: ?Sized> NonNull<T> {
     #[stable(feature = "nonnull", since = "1.25.0")]
     #[rustc_const_unstable(feature = "const_ptr_as_ref", issue = "91822")]
     #[must_use]
-    #[inline]
+    #[inline(always)]
     pub const unsafe fn as_mut<'a>(&mut self) -> &'a mut T {
         // SAFETY: the caller must guarantee that `self` meets all the
         // requirements for a mutable reference.
@@ -703,7 +703,7 @@ impl<T> NonNull<[T]> {
 #[stable(feature = "nonnull", since = "1.25.0")]
 #[rustc_const_unstable(feature = "const_clone", issue = "91805")]
 impl<T: ?Sized> const Clone for NonNull<T> {
-    #[inline]
+    #[inline(always)]
     fn clone(&self) -> Self {
         *self
     }

library/core/src/slice/mod.rs

@@ -465,7 +465,7 @@ impl<T> [T] {
     /// [`as_mut_ptr`]: slice::as_mut_ptr
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_stable(feature = "const_slice_as_ptr", since = "1.32.0")]
-    #[inline]
+    #[inline(always)]
     #[must_use]
     pub const fn as_ptr(&self) -> *const T {
         self as *const [T] as *const T
@@ -495,7 +495,7 @@ impl<T> [T] {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_stable(feature = "const_ptr_offset", since = "1.61.0")]
     #[rustc_allow_const_fn_unstable(const_mut_refs)]
-    #[inline]
+    #[inline(always)]
     #[must_use]
     pub const fn as_mut_ptr(&mut self) -> *mut T {
         self as *mut [T] as *mut T

library/core/src/str/mod.rs

@@ -396,7 +396,7 @@ impl str {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_stable(feature = "rustc_str_as_ptr", since = "1.32.0")]
     #[must_use]
-    #[inline]
+    #[inline(always)]
     pub const fn as_ptr(&self) -> *const u8 {
         self as *const str as *const u8
     }
@@ -411,7 +411,7 @@ impl str {
     /// modified in a way that it remains valid UTF-8.
     #[stable(feature = "str_as_mut_ptr", since = "1.36.0")]
     #[must_use]
-    #[inline]
+    #[inline(always)]
     pub fn as_mut_ptr(&mut self) -> *mut u8 {
         self as *mut str as *mut u8
     }