Make some float methods unstable `const fn`

Some float methods are now `const fn` under the `const_float_methods` feature gate.

In order to support `min`, `max`, `abs` and `copysign`, the implementation of some intrinsics had to be moved from Miri to rustc_const_eval.

6 files changed, 346 insertions, 192 deletions

diff --git a/library/core/src/intrinsics.rs b/library/core/src/intrinsics.rs
index 061fba9a1f7..3ae729e76e1 100644
--- a/library/core/src/intrinsics.rs
+++ b/library/core/src/intrinsics.rs
@@ -1848,154 +1848,6 @@ extern "rust-intrinsic" {
     #[cfg(not(bootstrap))]
     pub fn fmuladdf128(a: f128, b: f128, c: f128) -> f128;
 
-    /// Returns the absolute value of an `f16`.
-    ///
-    /// The stabilized version of this intrinsic is
-    /// [`f16::abs`](../../std/primitive.f16.html#method.abs)
-    #[rustc_nounwind]
-    pub fn fabsf16(x: f16) -> f16;
-    /// Returns the absolute value of an `f32`.
-    ///
-    /// The stabilized version of this intrinsic is
-    /// [`f32::abs`](../../std/primitive.f32.html#method.abs)
-    #[rustc_nounwind]
-    pub fn fabsf32(x: f32) -> f32;
-    /// Returns the absolute value of an `f64`.
-    ///
-    /// The stabilized version of this intrinsic is
-    /// [`f64::abs`](../../std/primitive.f64.html#method.abs)
-    #[rustc_nounwind]
-    pub fn fabsf64(x: f64) -> f64;
-    /// Returns the absolute value of an `f128`.
-    ///
-    /// The stabilized version of this intrinsic is
-    /// [`f128::abs`](../../std/primitive.f128.html#method.abs)
-    #[rustc_nounwind]
-    pub fn fabsf128(x: f128) -> f128;
-
-    /// Returns the minimum of two `f16` values.
-    ///
-    /// Note that, unlike most intrinsics, this is safe to call;
-    /// it does not require an `unsafe` block.
-    /// Therefore, implementations must not require the user to uphold
-    /// any safety invariants.
-    ///
-    /// The stabilized version of this intrinsic is
-    /// [`f16::min`]
-    #[rustc_safe_intrinsic]
-    #[rustc_nounwind]
-    pub fn minnumf16(x: f16, y: f16) -> f16;
-    /// Returns the minimum of two `f32` values.
-    ///
-    /// Note that, unlike most intrinsics, this is safe to call;
-    /// it does not require an `unsafe` block.
-    /// Therefore, implementations must not require the user to uphold
-    /// any safety invariants.
-    ///
-    /// The stabilized version of this intrinsic is
-    /// [`f32::min`]
-    #[rustc_safe_intrinsic]
-    #[rustc_nounwind]
-    pub fn minnumf32(x: f32, y: f32) -> f32;
-    /// Returns the minimum of two `f64` values.
-    ///
-    /// Note that, unlike most intrinsics, this is safe to call;
-    /// it does not require an `unsafe` block.
-    /// Therefore, implementations must not require the user to uphold
-    /// any safety invariants.
-    ///
-    /// The stabilized version of this intrinsic is
-    /// [`f64::min`]
-    #[rustc_safe_intrinsic]
-    #[rustc_nounwind]
-    pub fn minnumf64(x: f64, y: f64) -> f64;
-    /// Returns the minimum of two `f128` values.
-    ///
-    /// Note that, unlike most intrinsics, this is safe to call;
-    /// it does not require an `unsafe` block.
-    /// Therefore, implementations must not require the user to uphold
-    /// any safety invariants.
-    ///
-    /// The stabilized version of this intrinsic is
-    /// [`f128::min`]
-    #[rustc_safe_intrinsic]
-    #[rustc_nounwind]
-    pub fn minnumf128(x: f128, y: f128) -> f128;
-
-    /// Returns the maximum of two `f16` values.
-    ///
-    /// Note that, unlike most intrinsics, this is safe to call;
-    /// it does not require an `unsafe` block.
-    /// Therefore, implementations must not require the user to uphold
-    /// any safety invariants.
-    ///
-    /// The stabilized version of this intrinsic is
-    /// [`f16::max`]
-    #[rustc_safe_intrinsic]
-    #[rustc_nounwind]
-    pub fn maxnumf16(x: f16, y: f16) -> f16;
-    /// Returns the maximum of two `f32` values.
-    ///
-    /// Note that, unlike most intrinsics, this is safe to call;
-    /// it does not require an `unsafe` block.
-    /// Therefore, implementations must not require the user to uphold
-    /// any safety invariants.
-    ///
-    /// The stabilized version of this intrinsic is
-    /// [`f32::max`]
-    #[rustc_safe_intrinsic]
-    #[rustc_nounwind]
-    pub fn maxnumf32(x: f32, y: f32) -> f32;
-    /// Returns the maximum of two `f64` values.
-    ///
-    /// Note that, unlike most intrinsics, this is safe to call;
-    /// it does not require an `unsafe` block.
-    /// Therefore, implementations must not require the user to uphold
-    /// any safety invariants.
-    ///
-    /// The stabilized version of this intrinsic is
-    /// [`f64::max`]
-    #[rustc_safe_intrinsic]
-    #[rustc_nounwind]
-    pub fn maxnumf64(x: f64, y: f64) -> f64;
-    /// Returns the maximum of two `f128` values.
-    ///
-    /// Note that, unlike most intrinsics, this is safe to call;
-    /// it does not require an `unsafe` block.
-    /// Therefore, implementations must not require the user to uphold
-    /// any safety invariants.
-    ///
-    /// The stabilized version of this intrinsic is
-    /// [`f128::max`]
-    #[rustc_safe_intrinsic]
-    #[rustc_nounwind]
-    pub fn maxnumf128(x: f128, y: f128) -> f128;
-
-    /// Copies the sign from `y` to `x` for `f16` values.
-    ///
-    /// The stabilized version of this intrinsic is
-    /// [`f16::copysign`](../../std/primitive.f16.html#method.copysign)
-    #[rustc_nounwind]
-    pub fn copysignf16(x: f16, y: f16) -> f16;
-    /// Copies the sign from `y` to `x` for `f32` values.
-    ///
-    /// The stabilized version of this intrinsic is
-    /// [`f32::copysign`](../../std/primitive.f32.html#method.copysign)
-    #[rustc_nounwind]
-    pub fn copysignf32(x: f32, y: f32) -> f32;
-    /// Copies the sign from `y` to `x` for `f64` values.
-    ///
-    /// The stabilized version of this intrinsic is
-    /// [`f64::copysign`](../../std/primitive.f64.html#method.copysign)
-    #[rustc_nounwind]
-    pub fn copysignf64(x: f64, y: f64) -> f64;
-    /// Copies the sign from `y` to `x` for `f128` values.
-    ///
-    /// The stabilized version of this intrinsic is
-    /// [`f128::copysign`](../../std/primitive.f128.html#method.copysign)
-    #[rustc_nounwind]
-    pub fn copysignf128(x: f128, y: f128) -> f128;
-
     /// Returns the largest integer less than or equal to an `f16`.
     ///
     /// The stabilized version of this intrinsic is
@@ -3550,6 +3402,245 @@ pub const unsafe fn write_bytes<T>(dst: *mut T, val: u8, count: usize) {
     }
 }
 
+/// Returns the minimum of two `f16` values.
+///
+/// Note that, unlike most intrinsics, this is safe to call;
+/// it does not require an `unsafe` block.
+/// Therefore, implementations must not require the user to uphold
+/// any safety invariants.
+///
+/// The stabilized version of this intrinsic is
+/// [`f16::min`]
+#[rustc_nounwind]
+// #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
+#[rustc_const_unstable(feature = "f16", issue = "116909")]
+#[rustc_intrinsic]
+#[rustc_intrinsic_must_be_overridden]
+pub const fn minnumf16(_x: f16, _y: f16) -> f16 {
+    unimplemented!();
+}
+
+/// Returns the minimum of two `f32` values.
+///
+/// Note that, unlike most intrinsics, this is safe to call;
+/// it does not require an `unsafe` block.
+/// Therefore, implementations must not require the user to uphold
+/// any safety invariants.
+///
+/// The stabilized version of this intrinsic is
+/// [`f32::min`]
+#[rustc_nounwind]
+#[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
+#[rustc_intrinsic]
+#[rustc_intrinsic_must_be_overridden]
+pub const fn minnumf32(_x: f32, _y: f32) -> f32 {
+    unimplemented!();
+}
+
+/// Returns the minimum of two `f64` values.
+///
+/// Note that, unlike most intrinsics, this is safe to call;
+/// it does not require an `unsafe` block.
+/// Therefore, implementations must not require the user to uphold
+/// any safety invariants.
+///
+/// The stabilized version of this intrinsic is
+/// [`f64::min`]
+#[rustc_nounwind]
+#[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
+#[rustc_intrinsic]
+#[rustc_intrinsic_must_be_overridden]
+pub const fn minnumf64(_x: f64, _y: f64) -> f64 {
+    unimplemented!();
+}
+
+/// Returns the minimum of two `f128` values.
+///
+/// Note that, unlike most intrinsics, this is safe to call;
+/// it does not require an `unsafe` block.
+/// Therefore, implementations must not require the user to uphold
+/// any safety invariants.
+///
+/// The stabilized version of this intrinsic is
+/// [`f128::min`]
+#[rustc_nounwind]
+// #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
+#[rustc_const_unstable(feature = "f128", issue = "116909")]
+#[rustc_intrinsic]
+#[rustc_intrinsic_must_be_overridden]
+pub const fn minnumf128(_x: f128, _y: f128) -> f128 {
+    unimplemented!();
+}
+
+/// Returns the maximum of two `f16` values.
+///
+/// Note that, unlike most intrinsics, this is safe to call;
+/// it does not require an `unsafe` block.
+/// Therefore, implementations must not require the user to uphold
+/// any safety invariants.
+///
+/// The stabilized version of this intrinsic is
+/// [`f16::max`]
+#[rustc_nounwind]
+// #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
+#[rustc_const_unstable(feature = "f16", issue = "116909")]
+#[rustc_intrinsic]
+#[rustc_intrinsic_must_be_overridden]
+pub const fn maxnumf16(_x: f16, _y: f16) -> f16 {
+    unimplemented!();
+}
+
+/// Returns the maximum of two `f32` values.
+///
+/// Note that, unlike most intrinsics, this is safe to call;
+/// it does not require an `unsafe` block.
+/// Therefore, implementations must not require the user to uphold
+/// any safety invariants.
+///
+/// The stabilized version of this intrinsic is
+/// [`f32::max`]
+#[rustc_nounwind]
+#[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
+#[rustc_intrinsic]
+#[rustc_intrinsic_must_be_overridden]
+pub const fn maxnumf32(_x: f32, _y: f32) -> f32 {
+    unimplemented!();
+}
+
+/// Returns the maximum of two `f64` values.
+///
+/// Note that, unlike most intrinsics, this is safe to call;
+/// it does not require an `unsafe` block.
+/// Therefore, implementations must not require the user to uphold
+/// any safety invariants.
+///
+/// The stabilized version of this intrinsic is
+/// [`f64::max`]
+#[rustc_nounwind]
+#[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
+#[rustc_intrinsic]
+#[rustc_intrinsic_must_be_overridden]
+pub const fn maxnumf64(_x: f64, _y: f64) -> f64 {
+    unimplemented!();
+}
+
+/// Returns the maximum of two `f128` values.
+///
+/// Note that, unlike most intrinsics, this is safe to call;
+/// it does not require an `unsafe` block.
+/// Therefore, implementations must not require the user to uphold
+/// any safety invariants.
+///
+/// The stabilized version of this intrinsic is
+/// [`f128::max`]
+#[rustc_nounwind]
+// #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
+#[rustc_const_unstable(feature = "f128", issue = "116909")]
+#[rustc_intrinsic]
+#[rustc_intrinsic_must_be_overridden]
+pub const fn maxnumf128(_x: f128, _y: f128) -> f128 {
+    unimplemented!();
+}
+
+/// Returns the absolute value of an `f16`.
+///
+/// The stabilized version of this intrinsic is
+/// [`f16::abs`](../../std/primitive.f16.html#method.abs)
+#[rustc_nounwind]
+// #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
+#[rustc_const_unstable(feature = "f16", issue = "116909")]
+#[rustc_intrinsic]
+#[rustc_intrinsic_must_be_overridden]
+pub const unsafe fn fabsf16(_x: f16) -> f16 {
+    unimplemented!();
+}
+
+/// Returns the absolute value of an `f32`.
+///
+/// The stabilized version of this intrinsic is
+/// [`f32::abs`](../../std/primitive.f32.html#method.abs)
+#[rustc_nounwind]
+#[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
+#[rustc_intrinsic]
+#[rustc_intrinsic_must_be_overridden]
+pub const unsafe fn fabsf32(_x: f32) -> f32 {
+    unimplemented!();
+}
+
+/// Returns the absolute value of an `f64`.
+///
+/// The stabilized version of this intrinsic is
+/// [`f64::abs`](../../std/primitive.f64.html#method.abs)
+#[rustc_nounwind]
+#[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
+#[rustc_intrinsic]
+#[rustc_intrinsic_must_be_overridden]
+pub const unsafe fn fabsf64(_x: f64) -> f64 {
+    unimplemented!();
+}
+
+/// Returns the absolute value of an `f128`.
+///
+/// The stabilized version of this intrinsic is
+/// [`f128::abs`](../../std/primitive.f128.html#method.abs)
+#[rustc_nounwind]
+// #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
+#[rustc_const_unstable(feature = "f128", issue = "116909")]
+#[rustc_intrinsic]
+#[rustc_intrinsic_must_be_overridden]
+pub const unsafe fn fabsf128(_x: f128) -> f128 {
+    unimplemented!();
+}
+
+/// Copies the sign from `y` to `x` for `f16` values.
+///
+/// The stabilized version of this intrinsic is
+/// [`f16::copysign`](../../std/primitive.f16.html#method.copysign)
+#[rustc_nounwind]
+// #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
+#[rustc_const_unstable(feature = "f16", issue = "116909")]
+#[rustc_intrinsic]
+#[rustc_intrinsic_must_be_overridden]
+pub const unsafe fn copysignf16(_x: f16, _y: f16) -> f16 {
+    unimplemented!();
+}
+
+/// Copies the sign from `y` to `x` for `f32` values.
+///
+/// The stabilized version of this intrinsic is
+/// [`f32::copysign`](../../std/primitive.f32.html#method.copysign)
+#[rustc_nounwind]
+#[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
+#[rustc_intrinsic]
+#[rustc_intrinsic_must_be_overridden]
+pub const unsafe fn copysignf32(_x: f32, _y: f32) -> f32 {
+    unimplemented!();
+}
+/// Copies the sign from `y` to `x` for `f64` values.
+///
+/// The stabilized version of this intrinsic is
+/// [`f64::copysign`](../../std/primitive.f64.html#method.copysign)
+#[rustc_nounwind]
+#[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
+#[rustc_intrinsic]
+#[rustc_intrinsic_must_be_overridden]
+pub const unsafe fn copysignf64(_x: f64, _y: f64) -> f64 {
+    unimplemented!();
+}
+
+/// Copies the sign from `y` to `x` for `f128` values.
+///
+/// The stabilized version of this intrinsic is
+/// [`f128::copysign`](../../std/primitive.f128.html#method.copysign)
+#[rustc_nounwind]
+// #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
+#[rustc_const_unstable(feature = "f128", issue = "116909")]
+#[rustc_intrinsic]
+#[rustc_intrinsic_must_be_overridden]
+pub const unsafe fn copysignf128(_x: f128, _y: f128) -> f128 {
+    unimplemented!();
+}
+
 /// Inform Miri that a given pointer definitely has a certain alignment.
 #[cfg(miri)]
 pub(crate) const fn miri_promise_symbolic_alignment(ptr: *const (), align: usize) {
diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs
index 7f9a2152426..482e1f30b7e 100644
--- a/library/core/src/lib.rs
+++ b/library/core/src/lib.rs
@@ -120,6 +120,7 @@
 #![feature(const_char_encode_utf16)]
 #![feature(const_eval_select)]
 #![feature(const_exact_div)]
+#![feature(const_float_methods)]
 #![feature(const_fmt_arguments_new)]
 #![feature(const_hash)]
 #![feature(const_heap)]
diff --git a/library/core/src/num/f128.rs b/library/core/src/num/f128.rs
index 764df4fe4b0..5ab2ab50d7c 100644
--- a/library/core/src/num/f128.rs
+++ b/library/core/src/num/f128.rs
@@ -471,7 +471,7 @@ impl f128 {
     #[inline]
     #[must_use]
     #[unstable(feature = "f128", issue = "116909")]
-    pub fn is_sign_positive(self) -> bool {
+    pub const fn is_sign_positive(self) -> bool {
         !self.is_sign_negative()
     }
 
@@ -497,7 +497,7 @@ impl f128 {
     #[inline]
     #[must_use]
     #[unstable(feature = "f128", issue = "116909")]
-    pub fn is_sign_negative(self) -> bool {
+    pub const fn is_sign_negative(self) -> bool {
         // IEEE754 says: isSignMinus(x) is true if and only if x has negative sign. isSignMinus
         // applies to zeros and NaNs as well.
         // SAFETY: This is just transmuting to get the sign bit, it's fine.
@@ -538,7 +538,7 @@ impl f128 {
     #[inline]
     #[unstable(feature = "f128", issue = "116909")]
     // #[unstable(feature = "float_next_up_down", issue = "91399")]
-    pub fn next_up(self) -> Self {
+    pub const fn next_up(self) -> Self {
         // Some targets violate Rust's assumption of IEEE semantics, e.g. by flushing
         // denormals to zero. This is in general unsound and unsupported, but here
         // we do our best to still produce the correct result on such targets.
@@ -592,7 +592,7 @@ impl f128 {
     #[inline]
     #[unstable(feature = "f128", issue = "116909")]
     // #[unstable(feature = "float_next_up_down", issue = "91399")]
-    pub fn next_down(self) -> Self {
+    pub const fn next_down(self) -> Self {
         // Some targets violate Rust's assumption of IEEE semantics, e.g. by flushing
         // denormals to zero. This is in general unsound and unsupported, but here
         // we do our best to still produce the correct result on such targets.
@@ -627,8 +627,9 @@ impl f128 {
     /// ```
     #[inline]
     #[unstable(feature = "f128", issue = "116909")]
+    #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
     #[must_use = "this returns the result of the operation, without modifying the original"]
-    pub fn recip(self) -> Self {
+    pub const fn recip(self) -> Self {
         1.0 / self
     }
 
@@ -647,8 +648,9 @@ impl f128 {
     /// ```
     #[inline]
     #[unstable(feature = "f128", issue = "116909")]
+    #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
     #[must_use = "this returns the result of the operation, without modifying the original"]
-    pub fn to_degrees(self) -> Self {
+    pub const fn to_degrees(self) -> Self {
         // Use a literal for better precision.
         const PIS_IN_180: f128 = 57.2957795130823208767981548141051703324054724665643215491602_f128;
         self * PIS_IN_180
@@ -670,8 +672,9 @@ impl f128 {
     /// ```
     #[inline]
     #[unstable(feature = "f128", issue = "116909")]
+    #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
     #[must_use = "this returns the result of the operation, without modifying the original"]
-    pub fn to_radians(self) -> f128 {
+    pub const fn to_radians(self) -> f128 {
         // Use a literal for better precision.
         const RADS_PER_DEG: f128 =
             0.0174532925199432957692369076848861271344287188854172545609719_f128;
@@ -698,8 +701,9 @@ impl f128 {
     /// ```
     #[inline]
     #[unstable(feature = "f128", issue = "116909")]
+    #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
     #[must_use = "this returns the result of the comparison, without modifying either input"]
-    pub fn max(self, other: f128) -> f128 {
+    pub const fn max(self, other: f128) -> f128 {
         intrinsics::maxnumf128(self, other)
     }
 
@@ -723,8 +727,9 @@ impl f128 {
     /// ```
     #[inline]
     #[unstable(feature = "f128", issue = "116909")]
+    #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
     #[must_use = "this returns the result of the comparison, without modifying either input"]
-    pub fn min(self, other: f128) -> f128 {
+    pub const fn min(self, other: f128) -> f128 {
         intrinsics::minnumf128(self, other)
     }
 
@@ -757,7 +762,7 @@ impl f128 {
     #[unstable(feature = "f128", issue = "116909")]
     // #[unstable(feature = "float_minimum_maximum", issue = "91079")]
     #[must_use = "this returns the result of the comparison, without modifying either input"]
-    pub fn maximum(self, other: f128) -> f128 {
+    pub const fn maximum(self, other: f128) -> f128 {
         if self > other {
             self
         } else if other > self {
@@ -798,7 +803,7 @@ impl f128 {
     #[unstable(feature = "f128", issue = "116909")]
     // #[unstable(feature = "float_minimum_maximum", issue = "91079")]
     #[must_use = "this returns the result of the comparison, without modifying either input"]
-    pub fn minimum(self, other: f128) -> f128 {
+    pub const fn minimum(self, other: f128) -> f128 {
         if self < other {
             self
         } else if other < self {
@@ -1269,9 +1274,20 @@ impl f128 {
     /// ```
     #[inline]
     #[unstable(feature = "f128", issue = "116909")]
+    #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
     #[must_use = "method returns a new number and does not mutate the original value"]
-    pub fn clamp(mut self, min: f128, max: f128) -> f128 {
-        assert!(min <= max, "min > max, or either was NaN. min = {min:?}, max = {max:?}");
+    pub const fn clamp(mut self, min: f128, max: f128) -> f128 {
+        #[inline] // inline to avoid LLVM crash
+        const fn assert_at_const(min: f128, max: f128) {
+            // Note that we cannot format in constant expressions.
+            assert!(min <= max, "min > max, or either was NaN");
+        }
+        #[inline] // inline to avoid codegen regression
+        fn assert_at_rt(min: f128, max: f128) {
+            assert!(min <= max, "min > max, or either was NaN. min = {min:?}, max = {max:?}");
+        }
+        // FIXME(const-hack): We would prefer to have streamlined panics when formatters become const-friendly.
+        intrinsics::const_eval_select((min, max), assert_at_const, assert_at_rt);
         if self < min {
             self = min;
         }
diff --git a/library/core/src/num/f16.rs b/library/core/src/num/f16.rs
index 897fc8c105d..60a88496696 100644
--- a/library/core/src/num/f16.rs
+++ b/library/core/src/num/f16.rs
@@ -459,7 +459,7 @@ impl f16 {
     #[inline]
     #[must_use]
     #[unstable(feature = "f16", issue = "116909")]
-    pub fn is_sign_positive(self) -> bool {
+    pub const fn is_sign_positive(self) -> bool {
         !self.is_sign_negative()
     }
 
@@ -488,7 +488,7 @@ impl f16 {
     #[inline]
     #[must_use]
     #[unstable(feature = "f16", issue = "116909")]
-    pub fn is_sign_negative(self) -> bool {
+    pub const fn is_sign_negative(self) -> bool {
         // IEEE754 says: isSignMinus(x) is true if and only if x has negative sign. isSignMinus
         // applies to zeros and NaNs as well.
         // SAFETY: This is just transmuting to get the sign bit, it's fine.
@@ -529,7 +529,7 @@ impl f16 {
     #[inline]
     #[unstable(feature = "f16", issue = "116909")]
     // #[unstable(feature = "float_next_up_down", issue = "91399")]
-    pub fn next_up(self) -> Self {
+    pub const fn next_up(self) -> Self {
         // Some targets violate Rust's assumption of IEEE semantics, e.g. by flushing
         // denormals to zero. This is in general unsound and unsupported, but here
         // we do our best to still produce the correct result on such targets.
@@ -583,7 +583,7 @@ impl f16 {
     #[inline]
     #[unstable(feature = "f16", issue = "116909")]
     // #[unstable(feature = "float_next_up_down", issue = "91399")]
-    pub fn next_down(self) -> Self {
+    pub const fn next_down(self) -> Self {
         // Some targets violate Rust's assumption of IEEE semantics, e.g. by flushing
         // denormals to zero. This is in general unsound and unsupported, but here
         // we do our best to still produce the correct result on such targets.
@@ -618,8 +618,9 @@ impl f16 {
     /// ```
     #[inline]
     #[unstable(feature = "f16", issue = "116909")]
+    #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
     #[must_use = "this returns the result of the operation, without modifying the original"]
-    pub fn recip(self) -> Self {
+    pub const fn recip(self) -> Self {
         1.0 / self
     }
 
@@ -638,8 +639,9 @@ impl f16 {
     /// ```
     #[inline]
     #[unstable(feature = "f16", issue = "116909")]
+    #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
     #[must_use = "this returns the result of the operation, without modifying the original"]
-    pub fn to_degrees(self) -> Self {
+    pub const fn to_degrees(self) -> Self {
         // Use a literal for better precision.
         const PIS_IN_180: f16 = 57.2957795130823208767981548141051703_f16;
         self * PIS_IN_180
@@ -661,8 +663,9 @@ impl f16 {
     /// ```
     #[inline]
     #[unstable(feature = "f16", issue = "116909")]
+    #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
     #[must_use = "this returns the result of the operation, without modifying the original"]
-    pub fn to_radians(self) -> f16 {
+    pub const fn to_radians(self) -> f16 {
         // Use a literal for better precision.
         const RADS_PER_DEG: f16 = 0.017453292519943295769236907684886_f16;
         self * RADS_PER_DEG
@@ -687,8 +690,9 @@ impl f16 {
     /// ```
     #[inline]
     #[unstable(feature = "f16", issue = "116909")]
+    #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
     #[must_use = "this returns the result of the comparison, without modifying either input"]
-    pub fn max(self, other: f16) -> f16 {
+    pub const fn max(self, other: f16) -> f16 {
         intrinsics::maxnumf16(self, other)
     }
 
@@ -711,8 +715,9 @@ impl f16 {
     /// ```
     #[inline]
     #[unstable(feature = "f16", issue = "116909")]
+    #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
     #[must_use = "this returns the result of the comparison, without modifying either input"]
-    pub fn min(self, other: f16) -> f16 {
+    pub const fn min(self, other: f16) -> f16 {
         intrinsics::minnumf16(self, other)
     }
 
@@ -744,7 +749,7 @@ impl f16 {
     #[unstable(feature = "f16", issue = "116909")]
     // #[unstable(feature = "float_minimum_maximum", issue = "91079")]
     #[must_use = "this returns the result of the comparison, without modifying either input"]
-    pub fn maximum(self, other: f16) -> f16 {
+    pub const fn maximum(self, other: f16) -> f16 {
         if self > other {
             self
         } else if other > self {
@@ -784,7 +789,7 @@ impl f16 {
     #[unstable(feature = "f16", issue = "116909")]
     // #[unstable(feature = "float_minimum_maximum", issue = "91079")]
     #[must_use = "this returns the result of the comparison, without modifying either input"]
-    pub fn minimum(self, other: f16) -> f16 {
+    pub const fn minimum(self, other: f16) -> f16 {
         if self < other {
             self
         } else if other < self {
@@ -1244,9 +1249,20 @@ impl f16 {
     /// ```
     #[inline]
     #[unstable(feature = "f16", issue = "116909")]
+    #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
     #[must_use = "method returns a new number and does not mutate the original value"]
-    pub fn clamp(mut self, min: f16, max: f16) -> f16 {
-        assert!(min <= max, "min > max, or either was NaN. min = {min:?}, max = {max:?}");
+    pub const fn clamp(mut self, min: f16, max: f16) -> f16 {
+        #[inline] // inline to avoid LLVM crash
+        const fn assert_at_const(min: f16, max: f16) {
+            // Note that we cannot format in constant expressions.
+            assert!(min <= max, "min > max, or either was NaN");
+        }
+        #[inline] // inline to avoid codegen regression
+        fn assert_at_rt(min: f16, max: f16) {
+            assert!(min <= max, "min > max, or either was NaN. min = {min:?}, max = {max:?}");
+        }
+        // FIXME(const-hack): We would prefer to have streamlined panics when formatters become const-friendly.
+        intrinsics::const_eval_select((min, max), assert_at_const, assert_at_rt);
         if self < min {
             self = min;
         }
diff --git a/library/core/src/num/f32.rs b/library/core/src/num/f32.rs
index a9a2595c25c..05f5a08ad0a 100644
--- a/library/core/src/num/f32.rs
+++ b/library/core/src/num/f32.rs
@@ -828,8 +828,9 @@ impl f32 {
     /// ```
     #[must_use = "this returns the result of the operation, without modifying the original"]
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
     #[inline]
-    pub fn recip(self) -> f32 {
+    pub const fn recip(self) -> f32 {
         1.0 / self
     }
 
@@ -845,8 +846,9 @@ impl f32 {
     #[must_use = "this returns the result of the operation, \
                   without modifying the original"]
     #[stable(feature = "f32_deg_rad_conversions", since = "1.7.0")]
+    #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
     #[inline]
-    pub fn to_degrees(self) -> f32 {
+    pub const fn to_degrees(self) -> f32 {
         // Use a constant for better precision.
         const PIS_IN_180: f32 = 57.2957795130823208767981548141051703_f32;
         self * PIS_IN_180
@@ -864,8 +866,9 @@ impl f32 {
     #[must_use = "this returns the result of the operation, \
                   without modifying the original"]
     #[stable(feature = "f32_deg_rad_conversions", since = "1.7.0")]
+    #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
     #[inline]
-    pub fn to_radians(self) -> f32 {
+    pub const fn to_radians(self) -> f32 {
         const RADS_PER_DEG: f32 = consts::PI / 180.0;
         self * RADS_PER_DEG
     }
@@ -885,8 +888,9 @@ impl f32 {
     /// ```
     #[must_use = "this returns the result of the comparison, without modifying either input"]
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
     #[inline]
-    pub fn max(self, other: f32) -> f32 {
+    pub const fn max(self, other: f32) -> f32 {
         intrinsics::maxnumf32(self, other)
     }
 
@@ -905,8 +909,9 @@ impl f32 {
     /// ```
     #[must_use = "this returns the result of the comparison, without modifying either input"]
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
     #[inline]
-    pub fn min(self, other: f32) -> f32 {
+    pub const fn min(self, other: f32) -> f32 {
         intrinsics::minnumf32(self, other)
     }
 
@@ -933,7 +938,7 @@ impl f32 {
     #[must_use = "this returns the result of the comparison, without modifying either input"]
     #[unstable(feature = "float_minimum_maximum", issue = "91079")]
     #[inline]
-    pub fn maximum(self, other: f32) -> f32 {
+    pub const fn maximum(self, other: f32) -> f32 {
         if self > other {
             self
         } else if other > self {
@@ -968,7 +973,7 @@ impl f32 {
     #[must_use = "this returns the result of the comparison, without modifying either input"]
     #[unstable(feature = "float_minimum_maximum", issue = "91079")]
     #[inline]
-    pub fn minimum(self, other: f32) -> f32 {
+    pub const fn minimum(self, other: f32) -> f32 {
         if self < other {
             self
         } else if other < self {
@@ -1401,9 +1406,19 @@ impl f32 {
     /// ```
     #[must_use = "method returns a new number and does not mutate the original value"]
     #[stable(feature = "clamp", since = "1.50.0")]
+    #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
     #[inline]
-    pub fn clamp(mut self, min: f32, max: f32) -> f32 {
-        assert!(min <= max, "min > max, or either was NaN. min = {min:?}, max = {max:?}");
+    pub const fn clamp(mut self, min: f32, max: f32) -> f32 {
+        const fn assert_at_const(min: f32, max: f32) {
+            // Note that we cannot format in constant expressions.
+            assert!(min <= max, "min > max, or either was NaN");
+        }
+        #[inline] // inline to avoid codegen regression
+        fn assert_at_rt(min: f32, max: f32) {
+            assert!(min <= max, "min > max, or either was NaN. min = {min:?}, max = {max:?}");
+        }
+        // FIXME(const-hack): We would prefer to have streamlined panics when formatters become const-friendly.
+        intrinsics::const_eval_select((min, max), assert_at_const, assert_at_rt);
         if self < min {
             self = min;
         }
diff --git a/library/core/src/num/f64.rs b/library/core/src/num/f64.rs
index aa7a54ca650..89c6726d985 100644
--- a/library/core/src/num/f64.rs
+++ b/library/core/src/num/f64.rs
@@ -845,8 +845,9 @@ impl f64 {
     /// ```
     #[must_use = "this returns the result of the operation, without modifying the original"]
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
     #[inline]
-    pub fn recip(self) -> f64 {
+    pub const fn recip(self) -> f64 {
         1.0 / self
     }
 
@@ -862,8 +863,9 @@ impl f64 {
     #[must_use = "this returns the result of the operation, \
                   without modifying the original"]
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
     #[inline]
-    pub fn to_degrees(self) -> f64 {
+    pub const fn to_degrees(self) -> f64 {
         // The division here is correctly rounded with respect to the true
         // value of 180/π. (This differs from f32, where a constant must be
         // used to ensure a correctly rounded result.)
@@ -882,8 +884,9 @@ impl f64 {
     #[must_use = "this returns the result of the operation, \
                   without modifying the original"]
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
     #[inline]
-    pub fn to_radians(self) -> f64 {
+    pub const fn to_radians(self) -> f64 {
         const RADS_PER_DEG: f64 = consts::PI / 180.0;
         self * RADS_PER_DEG
     }
@@ -903,8 +906,9 @@ impl f64 {
     /// ```
     #[must_use = "this returns the result of the comparison, without modifying either input"]
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
     #[inline]
-    pub fn max(self, other: f64) -> f64 {
+    pub const fn max(self, other: f64) -> f64 {
         intrinsics::maxnumf64(self, other)
     }
 
@@ -923,8 +927,9 @@ impl f64 {
     /// ```
     #[must_use = "this returns the result of the comparison, without modifying either input"]
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
     #[inline]
-    pub fn min(self, other: f64) -> f64 {
+    pub const fn min(self, other: f64) -> f64 {
         intrinsics::minnumf64(self, other)
     }
 
@@ -951,7 +956,7 @@ impl f64 {
     #[must_use = "this returns the result of the comparison, without modifying either input"]
     #[unstable(feature = "float_minimum_maximum", issue = "91079")]
     #[inline]
-    pub fn maximum(self, other: f64) -> f64 {
+    pub const fn maximum(self, other: f64) -> f64 {
         if self > other {
             self
         } else if other > self {
@@ -986,7 +991,7 @@ impl f64 {
     #[must_use = "this returns the result of the comparison, without modifying either input"]
     #[unstable(feature = "float_minimum_maximum", issue = "91079")]
     #[inline]
-    pub fn minimum(self, other: f64) -> f64 {
+    pub const fn minimum(self, other: f64) -> f64 {
         if self < other {
             self
         } else if other < self {
@@ -1401,9 +1406,19 @@ impl f64 {
     /// ```
     #[must_use = "method returns a new number and does not mutate the original value"]
     #[stable(feature = "clamp", since = "1.50.0")]
+    #[rustc_const_unstable(feature = "const_float_methods", issue = "130843")]
     #[inline]
-    pub fn clamp(mut self, min: f64, max: f64) -> f64 {
-        assert!(min <= max, "min > max, or either was NaN. min = {min:?}, max = {max:?}");
+    pub const fn clamp(mut self, min: f64, max: f64) -> f64 {
+        const fn assert_at_const(min: f64, max: f64) {
+            // Note that we cannot format in constant expressions.
+            assert!(min <= max, "min > max, or either was NaN");
+        }
+        #[inline] // inline to avoid codegen regression
+        fn assert_at_rt(min: f64, max: f64) {
+            assert!(min <= max, "min > max, or either was NaN. min = {min:?}, max = {max:?}");
+        }
+        // FIXME(const-hack): We would prefer to have streamlined panics when formatters become const-friendly.
+        intrinsics::const_eval_select((min, max), assert_at_const, assert_at_rt);
         if self < min {
             self = min;
         }