Auto merge of rust-lang#138087 - tgross35:core-float-math, r=<try>

Initial implementation of `core_float_math`

Since [1], `compiler-builtins` makes a certain set of math symbols
weakly available on all platforms. This means we can begin exposing some
of the related functions in `core`, so begin this process here.

It is not possible to provide inherent methods in both `core` and `std`
while giving them different stability gates, so standalone functions are
added instead. This provides a way to experiment with the functionality
while unstable; once it is time to stabilize, they can be converted to
inherent.

For `f16` and `f128`, everything is unstable so we can move the inherent
methods.

The following are included to start:

* floor
* ceil
* round
* round_ties_even
* trunc
* fract
* mul_add
* div_euclid
* rem_euclid
* powi
* sqrt
* abs_sub
* cbrt

These mirror the set of functions that we have in `compiler-builtins`
since [1], with the exception of `powi` that has been there longer.

Tracking issue: rust-lang#137578

[1]: rust-lang/compiler-builtins#763

r? `@ghost`

try-job: aarch64-apple
try-job: aarch64-gnu
try-job: arm-android
tru-job: armhf-gnu
try-job: dist-various-1
try-job: dist-various-2
try-job: i686-msvc-1
try-job: test-various
try-job: x86_64-apple-1
try-job: x86_64-msvc-ext2

Author: bors

library/core/src/num/f128.rs

@@ -1366,3 +1366,380 @@ impl f128 {
         unsafe { intrinsics::copysignf128(self, sign) }
     }
 }
+
+// Functions in this module fall into `core_float_math`
+// FIXME(f16_f128): all doctests must be gated to platforms that have `long double` === `_Float128`
+// due to https://github.com/llvm/llvm-project/issues/44744. aarch64 linux matches this.
+// #[unstable(feature = "core_float_math", issue = "137578")]
+#[cfg(not(test))]
+impl f128 {
+    /// Returns the largest integer less than or equal to `self`.
+    ///
+    /// This function always returns the precise result.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(f128)]
+    /// # #[cfg(all(target_arch = "aarch64", target_os = "linux"))] {
+    ///
+    /// let f = 3.7_f128;
+    /// let g = 3.0_f128;
+    /// let h = -3.7_f128;
+    ///
+    /// assert_eq!(f.floor(), 3.0);
+    /// assert_eq!(g.floor(), 3.0);
+    /// assert_eq!(h.floor(), -4.0);
+    /// # }
+    /// ```
+    #[inline]
+    #[rustc_allow_incoherent_impl]
+    #[unstable(feature = "f128", issue = "116909")]
+    #[must_use = "method returns a new number and does not mutate the original value"]
+    pub fn floor(self) -> f128 {
+        // SAFETY: intrinsic with no preconditions
+        unsafe { intrinsics::floorf128(self) }
+    }
+
+    /// Returns the smallest integer greater than or equal to `self`.
+    ///
+    /// This function always returns the precise result.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(f128)]
+    /// # #[cfg(all(target_arch = "aarch64", target_os = "linux"))] {
+    ///
+    /// let f = 3.01_f128;
+    /// let g = 4.0_f128;
+    ///
+    /// assert_eq!(f.ceil(), 4.0);
+    /// assert_eq!(g.ceil(), 4.0);
+    /// # }
+    /// ```
+    #[inline]
+    #[doc(alias = "ceiling")]
+    #[rustc_allow_incoherent_impl]
+    #[unstable(feature = "f128", issue = "116909")]
+    #[must_use = "method returns a new number and does not mutate the original value"]
+    pub fn ceil(self) -> f128 {
+        // SAFETY: intrinsic with no preconditions
+        unsafe { intrinsics::ceilf128(self) }
+    }
+
+    /// Returns the nearest integer to `self`. If a value is half-way between two
+    /// integers, round away from `0.0`.
+    ///
+    /// This function always returns the precise result.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(f128)]
+    /// # #[cfg(all(target_arch = "aarch64", target_os = "linux"))] {
+    ///
+    /// let f = 3.3_f128;
+    /// let g = -3.3_f128;
+    /// let h = -3.7_f128;
+    /// let i = 3.5_f128;
+    /// let j = 4.5_f128;
+    ///
+    /// assert_eq!(f.round(), 3.0);
+    /// assert_eq!(g.round(), -3.0);
+    /// assert_eq!(h.round(), -4.0);
+    /// assert_eq!(i.round(), 4.0);
+    /// assert_eq!(j.round(), 5.0);
+    /// # }
+    /// ```
+    #[inline]
+    #[rustc_allow_incoherent_impl]
+    #[unstable(feature = "f128", issue = "116909")]
+    #[must_use = "method returns a new number and does not mutate the original value"]
+    pub fn round(self) -> f128 {
+        // SAFETY: intrinsic with no preconditions
+        unsafe { intrinsics::roundf128(self) }
+    }
+
+    /// Returns the nearest integer to a number. Rounds half-way cases to the number
+    /// with an even least significant digit.
+    ///
+    /// This function always returns the precise result.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(f128)]
+    /// # #[cfg(all(target_arch = "aarch64", target_os = "linux"))] {
+    ///
+    /// let f = 3.3_f128;
+    /// let g = -3.3_f128;
+    /// let h = 3.5_f128;
+    /// let i = 4.5_f128;
+    ///
+    /// assert_eq!(f.round_ties_even(), 3.0);
+    /// assert_eq!(g.round_ties_even(), -3.0);
+    /// assert_eq!(h.round_ties_even(), 4.0);
+    /// assert_eq!(i.round_ties_even(), 4.0);
+    /// # }
+    /// ```
+    #[inline]
+    #[rustc_allow_incoherent_impl]
+    #[unstable(feature = "f128", issue = "116909")]
+    #[must_use = "method returns a new number and does not mutate the original value"]
+    pub fn round_ties_even(self) -> f128 {
+        intrinsics::round_ties_even_f128(self)
+    }
+
+    /// Returns the integer part of `self`.
+    /// This means that non-integer numbers are always truncated towards zero.
+    ///
+    /// This function always returns the precise result.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(f128)]
+    /// # #[cfg(all(target_arch = "aarch64", target_os = "linux"))] {
+    ///
+    /// let f = 3.7_f128;
+    /// let g = 3.0_f128;
+    /// let h = -3.7_f128;
+    ///
+    /// assert_eq!(f.trunc(), 3.0);
+    /// assert_eq!(g.trunc(), 3.0);
+    /// assert_eq!(h.trunc(), -3.0);
+    /// # }
+    /// ```
+    #[inline]
+    #[doc(alias = "truncate")]
+    #[rustc_allow_incoherent_impl]
+    #[unstable(feature = "f128", issue = "116909")]
+    #[must_use = "method returns a new number and does not mutate the original value"]
+    pub fn trunc(self) -> f128 {
+        // SAFETY: intrinsic with no preconditions
+        unsafe { intrinsics::truncf128(self) }
+    }
+
+    /// Returns the fractional part of `self`.
+    ///
+    /// This function always returns the precise result.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(f128)]
+    /// # #[cfg(all(target_arch = "aarch64", target_os = "linux"))] {
+    ///
+    /// let x = 3.6_f128;
+    /// let y = -3.6_f128;
+    /// let abs_difference_x = (x.fract() - 0.6).abs();
+    /// let abs_difference_y = (y.fract() - (-0.6)).abs();
+    ///
+    /// assert!(abs_difference_x <= f128::EPSILON);
+    /// assert!(abs_difference_y <= f128::EPSILON);
+    /// # }
+    /// ```
+    #[inline]
+    #[rustc_allow_incoherent_impl]
+    #[unstable(feature = "f128", issue = "116909")]
+    #[must_use = "method returns a new number and does not mutate the original value"]
+    pub fn fract(self) -> f128 {
+        self - self.trunc()
+    }
+
+    /// Fused multiply-add. Computes `(self * a) + b` with only one rounding
+    /// error, yielding a more accurate result than an unfused multiply-add.
+    ///
+    /// Using `mul_add` *may* be more performant than an unfused multiply-add if
+    /// the target architecture has a dedicated `fma` CPU instruction. However,
+    /// this is not always true, and will be heavily dependant on designing
+    /// algorithms with specific target hardware in mind.
+    ///
+    /// # Precision
+    ///
+    /// The result of this operation is guaranteed to be the rounded
+    /// infinite-precision result. It is specified by IEEE 754 as
+    /// `fusedMultiplyAdd` and guaranteed not to change.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(f128)]
+    /// # #[cfg(all(target_arch = "aarch64", target_os = "linux"))] {
+    ///
+    /// let m = 10.0_f128;
+    /// let x = 4.0_f128;
+    /// let b = 60.0_f128;
+    ///
+    /// assert_eq!(m.mul_add(x, b), 100.0);
+    /// assert_eq!(m * x + b, 100.0);
+    ///
+    /// let one_plus_eps = 1.0_f128 + f128::EPSILON;
+    /// let one_minus_eps = 1.0_f128 - f128::EPSILON;
+    /// let minus_one = -1.0_f128;
+    ///
+    /// // The exact result (1 + eps) * (1 - eps) = 1 - eps * eps.
+    /// assert_eq!(one_plus_eps.mul_add(one_minus_eps, minus_one), -f128::EPSILON * f128::EPSILON);
+    /// // Different rounding with the non-fused multiply and add.
+    /// assert_eq!(one_plus_eps * one_minus_eps + minus_one, 0.0);
+    /// # }
+    /// ```
+    #[inline]
+    #[rustc_allow_incoherent_impl]
+    #[doc(alias = "fmaf128", alias = "fusedMultiplyAdd")]
+    #[unstable(feature = "f128", issue = "116909")]
+    #[must_use = "method returns a new number and does not mutate the original value"]
+    pub fn mul_add(self, a: f128, b: f128) -> f128 {
+        // SAFETY: intrinsic with no preconditions
+        unsafe { intrinsics::fmaf128(self, a, b) }
+    }
+
+    /// Calculates Euclidean division, the matching method for `rem_euclid`.
+    ///
+    /// This computes the integer `n` such that
+    /// `self = n * rhs + self.rem_euclid(rhs)`.
+    /// In other words, the result is `self / rhs` rounded to the integer `n`
+    /// such that `self >= n * rhs`.
+    ///
+    /// # Precision
+    ///
+    /// The result of this operation is guaranteed to be the rounded
+    /// infinite-precision result.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(f128)]
+    /// # #[cfg(all(target_arch = "aarch64", target_os = "linux"))] {
+    ///
+    /// let a: f128 = 7.0;
+    /// let b = 4.0;
+    /// assert_eq!(a.div_euclid(b), 1.0); // 7.0 > 4.0 * 1.0
+    /// assert_eq!((-a).div_euclid(b), -2.0); // -7.0 >= 4.0 * -2.0
+    /// assert_eq!(a.div_euclid(-b), -1.0); // 7.0 >= -4.0 * -1.0
+    /// assert_eq!((-a).div_euclid(-b), 2.0); // -7.0 >= -4.0 * 2.0
+    /// # }
+    /// ```
+    #[inline]
+    #[rustc_allow_incoherent_impl]
+    #[unstable(feature = "f128", issue = "116909")]
+    #[must_use = "method returns a new number and does not mutate the original value"]
+    pub fn div_euclid(self, rhs: f128) -> f128 {
+        let q = (self / rhs).trunc();
+        if self % rhs < 0.0 {
+            return if rhs > 0.0 { q - 1.0 } else { q + 1.0 };
+        }
+        q
+    }
+
+    /// Calculates the least nonnegative remainder of `self (mod rhs)`.
+    ///
+    /// In particular, the return value `r` satisfies `0.0 <= r < rhs.abs()` in
+    /// most cases. However, due to a floating point round-off error it can
+    /// result in `r == rhs.abs()`, violating the mathematical definition, if
+    /// `self` is much smaller than `rhs.abs()` in magnitude and `self < 0.0`.
+    /// This result is not an element of the function's codomain, but it is the
+    /// closest floating point number in the real numbers and thus fulfills the
+    /// property `self == self.div_euclid(rhs) * rhs + self.rem_euclid(rhs)`
+    /// approximately.
+    ///
+    /// # Precision
+    ///
+    /// The result of this operation is guaranteed to be the rounded
+    /// infinite-precision result.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(f128)]
+    /// # #[cfg(all(target_arch = "aarch64", target_os = "linux"))] {
+    ///
+    /// let a: f128 = 7.0;
+    /// let b = 4.0;
+    /// assert_eq!(a.rem_euclid(b), 3.0);
+    /// assert_eq!((-a).rem_euclid(b), 1.0);
+    /// assert_eq!(a.rem_euclid(-b), 3.0);
+    /// assert_eq!((-a).rem_euclid(-b), 1.0);
+    /// // limitation due to round-off error
+    /// assert!((-f128::EPSILON).rem_euclid(3.0) != 0.0);
+    /// # }
+    /// ```
+    #[inline]
+    #[rustc_allow_incoherent_impl]
+    #[doc(alias = "modulo", alias = "mod")]
+    #[unstable(feature = "f128", issue = "116909")]
+    #[must_use = "method returns a new number and does not mutate the original value"]
+    pub fn rem_euclid(self, rhs: f128) -> f128 {
+        let r = self % rhs;
+        if r < 0.0 { r + rhs.abs() } else { r }
+    }
+
+    /// Raises a number to an integer power.
+    ///
+    /// Using this function is generally faster than using `powf`.
+    /// It might have a different sequence of rounding operations than `powf`,
+    /// so the results are not guaranteed to agree.
+    ///
+    /// # Unspecified precision
+    ///
+    /// The precision of this function is non-deterministic. This means it varies by platform,
+    /// Rust version, and can even differ within the same execution from one invocation to the next.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(f128)]
+    /// # #[cfg(all(target_arch = "aarch64", target_os = "linux"))] {
+    ///
+    /// let x = 2.0_f128;
+    /// let abs_difference = (x.powi(2) - (x * x)).abs();
+    /// assert!(abs_difference <= f128::EPSILON);
+    ///
+    /// assert_eq!(f128::powi(f128::NAN, 0), 1.0);
+    /// # }
+    /// ```
+    #[inline]
+    #[rustc_allow_incoherent_impl]
+    #[unstable(feature = "f128", issue = "116909")]
+    #[must_use = "method returns a new number and does not mutate the original value"]
+    pub fn powi(self, n: i32) -> f128 {
+        // SAFETY: intrinsic with no preconditions
+        unsafe { intrinsics::powif128(self, n) }
+    }
+
+    /// Returns the square root of a number.
+    ///
+    /// Returns NaN if `self` is a negative number other than `-0.0`.
+    ///
+    /// # Precision
+    ///
+    /// The result of this operation is guaranteed to be the rounded
+    /// infinite-precision result. It is specified by IEEE 754 as `squareRoot`
+    /// and guaranteed not to change.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(f128)]
+    /// # #[cfg(all(target_arch = "aarch64", target_os = "linux"))] {
+    ///
+    /// let positive = 4.0_f128;
+    /// let negative = -4.0_f128;
+    /// let negative_zero = -0.0_f128;
+    ///
+    /// assert_eq!(positive.sqrt(), 2.0);
+    /// assert!(negative.sqrt().is_nan());
+    /// assert!(negative_zero.sqrt() == negative_zero);
+    /// # }
+    /// ```
+    #[inline]
+    #[doc(alias = "squareRoot")]
+    #[rustc_allow_incoherent_impl]
+    #[unstable(feature = "f128", issue = "116909")]
+    #[must_use = "method returns a new number and does not mutate the original value"]
+    pub fn sqrt(self) -> f128 {
+        // SAFETY: intrinsic with no preconditions
+        unsafe { intrinsics::sqrtf128(self) }
+    }
+}

library/core/src/num/f16.rs

@@ -0,0 +1,10 @@
+//! Bindings to math functions provided by the system `libm` or by the `libm` crate, exposed
+//! via `compiler-builtins`.
+
+// These symbols are all defined by `libm`, or by `compiler-builtins` on unsupported platforms.
+unsafe extern "C" {
+    pub(crate) fn cbrt(n: f64) -> f64;
+    pub(crate) fn cbrtf(n: f32) -> f32;
+    pub(crate) fn fdim(a: f64, b: f64) -> f64;
+    pub(crate) fn fdimf(a: f32, b: f32) -> f32;
+}

library/core/src/num/f32.rs

@@ -46,6 +46,7 @@ mod uint_macros; // import uint_impl!
 mod error;
 mod int_log10;
 mod int_sqrt;
+pub(crate) mod libm;
 mod nonzero;
 mod overflow_panic;
 mod saturating;

library/core/src/num/f64.rs

@@ -0,0 +1,8 @@
+mod build_shared {
+    include!("../std/build_shared.rs");
+}
+
+fn main() {
+    let cfg = build_shared::Config::from_env();
+    build_shared::configure_f16_f128(&cfg);
+}

library/core/src/num/libm.rs

@@ -0,0 +1,40 @@
+use std::fmt;
+use std::ops::{Add, Div, Mul, Rem, Sub};
+
+/// Verify that floats are within a tolerance of each other, 1.0e-6 by default.
+macro_rules! assert_approx_eq {
+    ($a:expr, $b:expr) => {{ assert_approx_eq!($a, $b, 1.0e-6) }};
+    ($a:expr, $b:expr, $lim:expr) => {{
+        let (a, b) = (&$a, &$b);
+        let diff = (*a - *b).abs();
+        assert!(
+            diff < $lim,
+            "{a:?} is not approximately equal to {b:?} (threshold {lim:?}, difference {diff:?})",
+            lim = $lim
+        );
+    }};
+}
+
+/// Helper function for testing numeric operations
+pub fn test_num<T>(ten: T, two: T)
+where
+    T: PartialEq
+        + Add<Output = T>
+        + Sub<Output = T>
+        + Mul<Output = T>
+        + Div<Output = T>
+        + Rem<Output = T>
+        + fmt::Debug
+        + Copy,
+{
+    assert_eq!(ten.add(two), ten + two);
+    assert_eq!(ten.sub(two), ten - two);
+    assert_eq!(ten.mul(two), ten * two);
+    assert_eq!(ten.div(two), ten / two);
+    assert_eq!(ten.rem(two), ten % two);
+}
+
+mod f128;
+mod f16;
+mod f32;
+mod f64;

library/core/src/num/mod.rs

@@ -18,6 +18,7 @@
 #![feature(const_eval_select)]
 #![feature(const_swap_nonoverlapping)]
 #![feature(const_trait_impl)]
+#![feature(core_float_math)]
 #![feature(core_intrinsics)]
 #![feature(core_intrinsics_fallbacks)]
 #![feature(core_io_borrowed_buf)]
@@ -30,6 +31,8 @@
 #![feature(exact_size_is_empty)]
 #![feature(extend_one)]
 #![feature(extern_types)]
+#![feature(f128)]
+#![feature(f16)]
 #![feature(float_minimum_maximum)]
 #![feature(flt2dec)]
 #![feature(fmt_internals)]
@@ -144,6 +147,7 @@ mod cmp;
 mod const_ptr;
 mod convert;
 mod ffi;
+mod floats;
 mod fmt;
 mod future;
 mod hash;

library/coretests/build.rs

@@ -1,23 +1,13 @@
 use std::env;
 
+use build_shared::Config;
+mod build_shared;
+
 fn main() {
     println!("cargo:rerun-if-changed=build.rs");
-    let target_arch = env::var("CARGO_CFG_TARGET_ARCH").expect("CARGO_CFG_TARGET_ARCH was not set");
-    let target_os = env::var("CARGO_CFG_TARGET_OS").expect("CARGO_CFG_TARGET_OS was not set");
-    let target_vendor =
-        env::var("CARGO_CFG_TARGET_VENDOR").expect("CARGO_CFG_TARGET_VENDOR was not set");
-    let target_env = env::var("CARGO_CFG_TARGET_ENV").expect("CARGO_CFG_TARGET_ENV was not set");
-    let target_abi = env::var("CARGO_CFG_TARGET_ABI").expect("CARGO_CFG_TARGET_ABI was not set");
-    let target_pointer_width: u32 = env::var("CARGO_CFG_TARGET_POINTER_WIDTH")
-        .expect("CARGO_CFG_TARGET_POINTER_WIDTH was not set")
-        .parse()
-        .unwrap();
-    let target_features: Vec<_> = env::var("CARGO_CFG_TARGET_FEATURE")
-        .unwrap_or_default()
-        .split(",")
-        .map(ToOwned::to_owned)
-        .collect();
-    let is_miri = env::var_os("CARGO_CFG_MIRI").is_some();
+
+    let cfg = Config::from_env();
+    let Config { ref target_arch, ref target_os, ref target_vendor, ref target_env, .. } = cfg;
 
     println!("cargo:rustc-check-cfg=cfg(netbsd10)");
     if target_os == "netbsd" && env::var("RUSTC_STD_NETBSD10").is_ok() {
@@ -84,110 +74,5 @@ fn main() {
 
     println!("cargo:rustc-env=STD_ENV_ARCH={}", env::var("CARGO_CFG_TARGET_ARCH").unwrap());
 
-    // Emit these on platforms that have no known ABI bugs, LLVM selection bugs, lowering bugs,
-    // missing symbols, or other problems, to determine when tests get run.
-    // If more broken platforms are found, please update the tracking issue at
-    // <https://github.com/rust-lang/rust/issues/116909>
-    //
-    // Some of these match arms are redundant; the goal is to separate reasons that the type is
-    // unreliable, even when multiple reasons might fail the same platform.
-    println!("cargo:rustc-check-cfg=cfg(reliable_f16)");
-    println!("cargo:rustc-check-cfg=cfg(reliable_f128)");
-
-    // This is a step beyond only having the types and basic functions available. Math functions
-    // aren't consistently available or correct.
-    println!("cargo:rustc-check-cfg=cfg(reliable_f16_math)");
-    println!("cargo:rustc-check-cfg=cfg(reliable_f128_math)");
-
-    let has_reliable_f16 = match (target_arch.as_str(), target_os.as_str()) {
-        // We can always enable these in Miri as that is not affected by codegen bugs.
-        _ if is_miri => true,
-        // Selection failure <https://github.com/llvm/llvm-project/issues/50374>
-        ("s390x", _) => false,
-        // Unsupported <https://github.com/llvm/llvm-project/issues/94434>
-        ("arm64ec", _) => false,
-        // LLVM crash <https://github.com/llvm/llvm-project/issues/129394>
-        ("aarch64", _) if !target_features.iter().any(|f| f == "neon") => false,
-        // MinGW ABI bugs <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115054>
-        ("x86_64", "windows") if target_env == "gnu" && target_abi != "llvm" => false,
-        // Infinite recursion <https://github.com/llvm/llvm-project/issues/97981>
-        ("csky", _) => false,
-        ("hexagon", _) => false,
-        ("loongarch64", _) => false,
-        ("powerpc" | "powerpc64", _) => false,
-        ("sparc" | "sparc64", _) => false,
-        ("wasm32" | "wasm64", _) => false,
-        // `f16` support only requires that symbols converting to and from `f32` are available. We
-        // provide these in `compiler-builtins`, so `f16` should be available on all platforms that
-        // do not have other ABI issues or LLVM crashes.
-        _ => true,
-    };
-
-    let has_reliable_f128 = match (target_arch.as_str(), target_os.as_str()) {
-        // We can always enable these in Miri as that is not affected by codegen bugs.
-        _ if is_miri => true,
-        // Unsupported <https://github.com/llvm/llvm-project/issues/94434>
-        ("arm64ec", _) => false,
-        // Selection bug <https://github.com/llvm/llvm-project/issues/96432>
-        ("mips64" | "mips64r6", _) => false,
-        // Selection bug <https://github.com/llvm/llvm-project/issues/95471>
-        ("nvptx64", _) => false,
-        // ABI bugs <https://github.com/rust-lang/rust/issues/125109> et al. (full
-        // list at <https://github.com/rust-lang/rust/issues/116909>)
-        ("powerpc" | "powerpc64", _) => false,
-        // ABI unsupported  <https://github.com/llvm/llvm-project/issues/41838>
-        ("sparc", _) => false,
-        // Stack alignment bug <https://github.com/llvm/llvm-project/issues/77401>. NB: tests may
-        // not fail if our compiler-builtins is linked.
-        ("x86", _) => false,
-        // MinGW ABI bugs <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115054>
-        ("x86_64", "windows") if target_env == "gnu" && target_abi != "llvm" => false,
-        // There are no known problems on other platforms, so the only requirement is that symbols
-        // are available. `compiler-builtins` provides all symbols required for core `f128`
-        // support, so this should work for everything else.
-        _ => true,
-    };
-
-    // Configure platforms that have reliable basics but may have unreliable math.
-
-    // LLVM is currently adding missing routines, <https://github.com/llvm/llvm-project/issues/93566>
-    let has_reliable_f16_math = has_reliable_f16
-        && match (target_arch.as_str(), target_os.as_str()) {
-            // FIXME: Disabled on Miri as the intrinsics are not implemented yet.
-            _ if is_miri => false,
-            // x86 has a crash for `powi`: <https://github.com/llvm/llvm-project/issues/105747>
-            ("x86" | "x86_64", _) => false,
-            // Assume that working `f16` means working `f16` math for most platforms, since
-            // operations just go through `f32`.
-            _ => true,
-        };
-
-    let has_reliable_f128_math = has_reliable_f128
-        && match (target_arch.as_str(), target_os.as_str()) {
-            // FIXME: Disabled on Miri as the intrinsics are not implemented yet.
-            _ if is_miri => false,
-            // LLVM lowers `fp128` math to `long double` symbols even on platforms where
-            // `long double` is not IEEE binary128. See
-            // <https://github.com/llvm/llvm-project/issues/44744>.
-            //
-            // This rules out anything that doesn't have `long double` = `binary128`; <= 32 bits
-            // (ld is `f64`), anything other than Linux (Windows and MacOS use `f64`), and `x86`
-            // (ld is 80-bit extended precision).
-            ("x86_64", _) => false,
-            (_, "linux") if target_pointer_width == 64 => true,
-            _ => false,
-        };
-
-    if has_reliable_f16 {
-        println!("cargo:rustc-cfg=reliable_f16");
-    }
-    if has_reliable_f128 {
-        println!("cargo:rustc-cfg=reliable_f128");
-    }
-    if has_reliable_f16_math {
-        println!("cargo:rustc-cfg=reliable_f16_math");
-    }
-    if has_reliable_f128_math {
-        println!("cargo:rustc-cfg=reliable_f128_math");
-    }
+    build_shared::configure_f16_f128(&cfg);
 }

library/coretests/tests/floats/f128.rs

@@ -0,0 +1,150 @@
+// This portion of configuration is shared between `std` and `coretests`.
+
+use std::env;
+
+#[allow(dead_code)] // Not all importers of this file use all fields
+pub struct Config {
+    pub target_arch: String,
+    pub target_os: String,
+    pub target_vendor: String,
+    pub target_env: String,
+    pub target_abi: String,
+    pub target_pointer_width: u32,
+    pub target_features: Vec<String>,
+    pub is_miri: bool,
+}
+
+impl Config {
+    pub fn from_env() -> Self {
+        Self {
+            target_arch: env::var("CARGO_CFG_TARGET_ARCH")
+                .expect("CARGO_CFG_TARGET_ARCH was not set"),
+            target_os: env::var("CARGO_CFG_TARGET_OS").expect("CARGO_CFG_TARGET_OS was not set"),
+            target_vendor: env::var("CARGO_CFG_TARGET_VENDOR")
+                .expect("CARGO_CFG_TARGET_VENDOR was not set"),
+            target_env: env::var("CARGO_CFG_TARGET_ENV").expect("CARGO_CFG_TARGET_ENV was not set"),
+            target_abi: env::var("CARGO_CFG_TARGET_ABI").expect("CARGO_CFG_TARGET_ABI was not set"),
+            target_pointer_width: env::var("CARGO_CFG_TARGET_POINTER_WIDTH")
+                .expect("CARGO_CFG_TARGET_POINTER_WIDTH was not set")
+                .parse()
+                .unwrap(),
+            target_features: env::var("CARGO_CFG_TARGET_FEATURE")
+                .unwrap_or_default()
+                .split(",")
+                .map(ToOwned::to_owned)
+                .collect(),
+            is_miri: env::var_os("CARGO_CFG_MIRI").is_some(),
+        }
+    }
+}
+
+pub fn configure_f16_f128(cfg: &Config) {
+    // Emit these on platforms that have no known ABI bugs, LLVM selection bugs, lowering bugs,
+    // missing symbols, or other problems, to determine when tests get run.
+    // If more broken platforms are found, please update the tracking issue at
+    // <https://github.com/rust-lang/rust/issues/116909>
+    //
+    // Some of these match arms are redundant; the goal is to separate reasons that the type is
+    // unreliable, even when multiple reasons might fail the same platform.
+    println!("cargo:rustc-check-cfg=cfg(reliable_f16)");
+    println!("cargo:rustc-check-cfg=cfg(reliable_f128)");
+
+    // This is a step beyond only having the types and basic functions available. Math functions
+    // aren't consistently available or correct.
+    println!("cargo:rustc-check-cfg=cfg(reliable_f16_math)");
+    println!("cargo:rustc-check-cfg=cfg(reliable_f128_math)");
+
+    let target_arch = cfg.target_arch.as_str();
+    let target_os = cfg.target_os.as_str();
+
+    let has_reliable_f16 = match (target_arch, target_os) {
+        // We can always enable these in Miri as that is not affected by codegen bugs.
+        _ if cfg.is_miri => true,
+        // Selection failure <https://github.com/llvm/llvm-project/issues/50374>
+        ("s390x", _) => false,
+        // Unsupported <https://github.com/llvm/llvm-project/issues/94434>
+        ("arm64ec", _) => false,
+        // MinGW ABI bugs <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115054>
+        ("x86_64", "windows") if cfg.target_env == "gnu" && cfg.target_abi != "llvm" => false,
+        // Infinite recursion <https://github.com/llvm/llvm-project/issues/97981>
+        ("csky", _) => false,
+        ("hexagon", _) => false,
+        ("loongarch64", _) => false,
+        ("mips" | "mips64" | "mips32r6" | "mips64r6", _) => false,
+        ("powerpc" | "powerpc64", _) => false,
+        ("sparc" | "sparc64", _) => false,
+        ("wasm32" | "wasm64", _) => false,
+        // `f16` support only requires that symbols converting to and from `f32` are available. We
+        // provide these in `compiler-builtins`, so `f16` should be available on all platforms that
+        // do not have other ABI issues or LLVM crashes.
+        _ => true,
+    };
+
+    let has_reliable_f128 = match (target_arch, target_os) {
+        // We can always enable these in Miri as that is not affected by codegen bugs.
+        _ if cfg.is_miri => true,
+        // Unsupported <https://github.com/llvm/llvm-project/issues/94434>
+        ("arm64ec", _) => false,
+        // Selection bug <https://github.com/llvm/llvm-project/issues/96432>
+        ("mips64" | "mips64r6", _) => false,
+        // Selection bug <https://github.com/llvm/llvm-project/issues/95471>
+        ("nvptx64", _) => false,
+        // ABI bugs <https://github.com/rust-lang/rust/issues/125109> et al. (full
+        // list at <https://github.com/rust-lang/rust/issues/116909>)
+        ("powerpc" | "powerpc64", _) => false,
+        // ABI unsupported  <https://github.com/llvm/llvm-project/issues/41838>
+        ("sparc", _) => false,
+        // Stack alignment bug <https://github.com/llvm/llvm-project/issues/77401>. NB: tests may
+        // not fail if our compiler-builtins is linked.
+        ("x86", _) => false,
+        // MinGW ABI bugs <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115054>
+        ("x86_64", "windows") if cfg.target_env == "gnu" && cfg.target_abi != "llvm" => false,
+        // There are no known problems on other platforms, so the only requirement is that symbols
+        // are available. `compiler-builtins` provides all symbols required for core `f128`
+        // support, so this should work for everything else.
+        _ => true,
+    };
+
+    // Configure platforms that have reliable basics but may have unreliable math.
+
+    // LLVM is currently adding missing routines, <https://github.com/llvm/llvm-project/issues/93566>
+    let has_reliable_f16_math = has_reliable_f16
+        && match (target_arch, target_os) {
+            // FIXME: Disabled on Miri as the intrinsics are not implemented yet.
+            _ if cfg.is_miri => false,
+            // x86 has a crash for `powi`: <https://github.com/llvm/llvm-project/issues/105747>
+            ("x86" | "x86_64", _) => false,
+            // Assume that working `f16` means working `f16` math for most platforms, since
+            // operations just go through `f32`.
+            _ => true,
+        };
+
+    let has_reliable_f128_math = has_reliable_f128
+        && match (target_arch, target_os) {
+            // FIXME: Disabled on Miri as the intrinsics are not implemented yet.
+            _ if cfg.is_miri => false,
+            // LLVM lowers `fp128` math to `long double` symbols even on platforms where
+            // `long double` is not IEEE binary128. See
+            // <https://github.com/llvm/llvm-project/issues/44744>.
+            //
+            // This rules out anything that doesn't have `long double` = `binary128`; <= 32 bits
+            // (ld is `f64`), anything other than Linux (Windows and MacOS use `f64`), and `x86`
+            // (ld is 80-bit extended precision).
+            ("x86_64", _) => false,
+            (_, "linux") if cfg.target_pointer_width == 64 => true,
+            _ => false,
+        };
+
+    if has_reliable_f16 {
+        println!("cargo:rustc-cfg=reliable_f16");
+    }
+    if has_reliable_f128 {
+        println!("cargo:rustc-cfg=reliable_f128");
+    }
+    if has_reliable_f16_math {
+        println!("cargo:rustc-cfg=reliable_f16_math");
+    }
+    if has_reliable_f128_math {
+        println!("cargo:rustc-cfg=reliable_f128_math");
+    }
+}

library/coretests/tests/floats/f16.rs

@@ -14,335 +14,6 @@ use crate::sys::cmath;
 
 #[cfg(not(test))]
 impl f128 {
-    /// Returns the largest integer less than or equal to `self`.
-    ///
-    /// This function always returns the precise result.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// #![feature(f128)]
-    /// # #[cfg(reliable_f128_math)] {
-    ///
-    /// let f = 3.7_f128;
-    /// let g = 3.0_f128;
-    /// let h = -3.7_f128;
-    ///
-    /// assert_eq!(f.floor(), 3.0);
-    /// assert_eq!(g.floor(), 3.0);
-    /// assert_eq!(h.floor(), -4.0);
-    /// # }
-    /// ```
-    #[inline]
-    #[rustc_allow_incoherent_impl]
-    #[unstable(feature = "f128", issue = "116909")]
-    #[must_use = "method returns a new number and does not mutate the original value"]
-    pub fn floor(self) -> f128 {
-        unsafe { intrinsics::floorf128(self) }
-    }
-
-    /// Returns the smallest integer greater than or equal to `self`.
-    ///
-    /// This function always returns the precise result.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// #![feature(f128)]
-    /// # #[cfg(reliable_f128_math)] {
-    ///
-    /// let f = 3.01_f128;
-    /// let g = 4.0_f128;
-    ///
-    /// assert_eq!(f.ceil(), 4.0);
-    /// assert_eq!(g.ceil(), 4.0);
-    /// # }
-    /// ```
-    #[inline]
-    #[doc(alias = "ceiling")]
-    #[rustc_allow_incoherent_impl]
-    #[unstable(feature = "f128", issue = "116909")]
-    #[must_use = "method returns a new number and does not mutate the original value"]
-    pub fn ceil(self) -> f128 {
-        unsafe { intrinsics::ceilf128(self) }
-    }
-
-    /// Returns the nearest integer to `self`. If a value is half-way between two
-    /// integers, round away from `0.0`.
-    ///
-    /// This function always returns the precise result.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// #![feature(f128)]
-    /// # #[cfg(reliable_f128_math)] {
-    ///
-    /// let f = 3.3_f128;
-    /// let g = -3.3_f128;
-    /// let h = -3.7_f128;
-    /// let i = 3.5_f128;
-    /// let j = 4.5_f128;
-    ///
-    /// assert_eq!(f.round(), 3.0);
-    /// assert_eq!(g.round(), -3.0);
-    /// assert_eq!(h.round(), -4.0);
-    /// assert_eq!(i.round(), 4.0);
-    /// assert_eq!(j.round(), 5.0);
-    /// # }
-    /// ```
-    #[inline]
-    #[rustc_allow_incoherent_impl]
-    #[unstable(feature = "f128", issue = "116909")]
-    #[must_use = "method returns a new number and does not mutate the original value"]
-    pub fn round(self) -> f128 {
-        unsafe { intrinsics::roundf128(self) }
-    }
-
-    /// Returns the nearest integer to a number. Rounds half-way cases to the number
-    /// with an even least significant digit.
-    ///
-    /// This function always returns the precise result.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// #![feature(f128)]
-    /// # #[cfg(reliable_f128_math)] {
-    ///
-    /// let f = 3.3_f128;
-    /// let g = -3.3_f128;
-    /// let h = 3.5_f128;
-    /// let i = 4.5_f128;
-    ///
-    /// assert_eq!(f.round_ties_even(), 3.0);
-    /// assert_eq!(g.round_ties_even(), -3.0);
-    /// assert_eq!(h.round_ties_even(), 4.0);
-    /// assert_eq!(i.round_ties_even(), 4.0);
-    /// # }
-    /// ```
-    #[inline]
-    #[rustc_allow_incoherent_impl]
-    #[unstable(feature = "f128", issue = "116909")]
-    #[must_use = "method returns a new number and does not mutate the original value"]
-    pub fn round_ties_even(self) -> f128 {
-        intrinsics::round_ties_even_f128(self)
-    }
-
-    /// Returns the integer part of `self`.
-    /// This means that non-integer numbers are always truncated towards zero.
-    ///
-    /// This function always returns the precise result.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// #![feature(f128)]
-    /// # #[cfg(reliable_f128_math)] {
-    ///
-    /// let f = 3.7_f128;
-    /// let g = 3.0_f128;
-    /// let h = -3.7_f128;
-    ///
-    /// assert_eq!(f.trunc(), 3.0);
-    /// assert_eq!(g.trunc(), 3.0);
-    /// assert_eq!(h.trunc(), -3.0);
-    /// # }
-    /// ```
-    #[inline]
-    #[doc(alias = "truncate")]
-    #[rustc_allow_incoherent_impl]
-    #[unstable(feature = "f128", issue = "116909")]
-    #[must_use = "method returns a new number and does not mutate the original value"]
-    pub fn trunc(self) -> f128 {
-        unsafe { intrinsics::truncf128(self) }
-    }
-
-    /// Returns the fractional part of `self`.
-    ///
-    /// This function always returns the precise result.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// #![feature(f128)]
-    /// # #[cfg(reliable_f128_math)] {
-    ///
-    /// let x = 3.6_f128;
-    /// let y = -3.6_f128;
-    /// let abs_difference_x = (x.fract() - 0.6).abs();
-    /// let abs_difference_y = (y.fract() - (-0.6)).abs();
-    ///
-    /// assert!(abs_difference_x <= f128::EPSILON);
-    /// assert!(abs_difference_y <= f128::EPSILON);
-    /// # }
-    /// ```
-    #[inline]
-    #[rustc_allow_incoherent_impl]
-    #[unstable(feature = "f128", issue = "116909")]
-    #[must_use = "method returns a new number and does not mutate the original value"]
-    pub fn fract(self) -> f128 {
-        self - self.trunc()
-    }
-
-    /// Fused multiply-add. Computes `(self * a) + b` with only one rounding
-    /// error, yielding a more accurate result than an unfused multiply-add.
-    ///
-    /// Using `mul_add` *may* be more performant than an unfused multiply-add if
-    /// the target architecture has a dedicated `fma` CPU instruction. However,
-    /// this is not always true, and will be heavily dependant on designing
-    /// algorithms with specific target hardware in mind.
-    ///
-    /// # Precision
-    ///
-    /// The result of this operation is guaranteed to be the rounded
-    /// infinite-precision result. It is specified by IEEE 754 as
-    /// `fusedMultiplyAdd` and guaranteed not to change.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// #![feature(f128)]
-    /// # #[cfg(reliable_f128_math)] {
-    ///
-    /// let m = 10.0_f128;
-    /// let x = 4.0_f128;
-    /// let b = 60.0_f128;
-    ///
-    /// assert_eq!(m.mul_add(x, b), 100.0);
-    /// assert_eq!(m * x + b, 100.0);
-    ///
-    /// let one_plus_eps = 1.0_f128 + f128::EPSILON;
-    /// let one_minus_eps = 1.0_f128 - f128::EPSILON;
-    /// let minus_one = -1.0_f128;
-    ///
-    /// // The exact result (1 + eps) * (1 - eps) = 1 - eps * eps.
-    /// assert_eq!(one_plus_eps.mul_add(one_minus_eps, minus_one), -f128::EPSILON * f128::EPSILON);
-    /// // Different rounding with the non-fused multiply and add.
-    /// assert_eq!(one_plus_eps * one_minus_eps + minus_one, 0.0);
-    /// # }
-    /// ```
-    #[inline]
-    #[rustc_allow_incoherent_impl]
-    #[doc(alias = "fmaf128", alias = "fusedMultiplyAdd")]
-    #[unstable(feature = "f128", issue = "116909")]
-    #[must_use = "method returns a new number and does not mutate the original value"]
-    pub fn mul_add(self, a: f128, b: f128) -> f128 {
-        unsafe { intrinsics::fmaf128(self, a, b) }
-    }
-
-    /// Calculates Euclidean division, the matching method for `rem_euclid`.
-    ///
-    /// This computes the integer `n` such that
-    /// `self = n * rhs + self.rem_euclid(rhs)`.
-    /// In other words, the result is `self / rhs` rounded to the integer `n`
-    /// such that `self >= n * rhs`.
-    ///
-    /// # Precision
-    ///
-    /// The result of this operation is guaranteed to be the rounded
-    /// infinite-precision result.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// #![feature(f128)]
-    /// # #[cfg(reliable_f128_math)] {
-    ///
-    /// let a: f128 = 7.0;
-    /// let b = 4.0;
-    /// assert_eq!(a.div_euclid(b), 1.0); // 7.0 > 4.0 * 1.0
-    /// assert_eq!((-a).div_euclid(b), -2.0); // -7.0 >= 4.0 * -2.0
-    /// assert_eq!(a.div_euclid(-b), -1.0); // 7.0 >= -4.0 * -1.0
-    /// assert_eq!((-a).div_euclid(-b), 2.0); // -7.0 >= -4.0 * 2.0
-    /// # }
-    /// ```
-    #[inline]
-    #[rustc_allow_incoherent_impl]
-    #[unstable(feature = "f128", issue = "116909")]
-    #[must_use = "method returns a new number and does not mutate the original value"]
-    pub fn div_euclid(self, rhs: f128) -> f128 {
-        let q = (self / rhs).trunc();
-        if self % rhs < 0.0 {
-            return if rhs > 0.0 { q - 1.0 } else { q + 1.0 };
-        }
-        q
-    }
-
-    /// Calculates the least nonnegative remainder of `self (mod rhs)`.
-    ///
-    /// In particular, the return value `r` satisfies `0.0 <= r < rhs.abs()` in
-    /// most cases. However, due to a floating point round-off error it can
-    /// result in `r == rhs.abs()`, violating the mathematical definition, if
-    /// `self` is much smaller than `rhs.abs()` in magnitude and `self < 0.0`.
-    /// This result is not an element of the function's codomain, but it is the
-    /// closest floating point number in the real numbers and thus fulfills the
-    /// property `self == self.div_euclid(rhs) * rhs + self.rem_euclid(rhs)`
-    /// approximately.
-    ///
-    /// # Precision
-    ///
-    /// The result of this operation is guaranteed to be the rounded
-    /// infinite-precision result.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// #![feature(f128)]
-    /// # #[cfg(reliable_f128_math)] {
-    ///
-    /// let a: f128 = 7.0;
-    /// let b = 4.0;
-    /// assert_eq!(a.rem_euclid(b), 3.0);
-    /// assert_eq!((-a).rem_euclid(b), 1.0);
-    /// assert_eq!(a.rem_euclid(-b), 3.0);
-    /// assert_eq!((-a).rem_euclid(-b), 1.0);
-    /// // limitation due to round-off error
-    /// assert!((-f128::EPSILON).rem_euclid(3.0) != 0.0);
-    /// # }
-    /// ```
-    #[inline]
-    #[rustc_allow_incoherent_impl]
-    #[doc(alias = "modulo", alias = "mod")]
-    #[unstable(feature = "f128", issue = "116909")]
-    #[must_use = "method returns a new number and does not mutate the original value"]
-    pub fn rem_euclid(self, rhs: f128) -> f128 {
-        let r = self % rhs;
-        if r < 0.0 { r + rhs.abs() } else { r }
-    }
-
-    /// Raises a number to an integer power.
-    ///
-    /// Using this function is generally faster than using `powf`.
-    /// It might have a different sequence of rounding operations than `powf`,
-    /// so the results are not guaranteed to agree.
-    ///
-    /// # Unspecified precision
-    ///
-    /// The precision of this function is non-deterministic. This means it varies by platform,
-    /// Rust version, and can even differ within the same execution from one invocation to the next.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// #![feature(f128)]
-    /// # #[cfg(reliable_f128_math)] {
-    ///
-    /// let x = 2.0_f128;
-    /// let abs_difference = (x.powi(2) - (x * x)).abs();
-    /// assert!(abs_difference <= f128::EPSILON);
-    ///
-    /// assert_eq!(f128::powi(f128::NAN, 0), 1.0);
-    /// # }
-    /// ```
-    #[inline]
-    #[rustc_allow_incoherent_impl]
-    #[unstable(feature = "f128", issue = "116909")]
-    #[must_use = "method returns a new number and does not mutate the original value"]
-    pub fn powi(self, n: i32) -> f128 {
-        unsafe { intrinsics::powif128(self, n) }
-    }
-
     /// Raises a number to a floating point power.
     ///
     /// # Unspecified precision
@@ -372,40 +43,6 @@ impl f128 {
         unsafe { intrinsics::powf128(self, n) }
     }
 
-    /// Returns the square root of a number.
-    ///
-    /// Returns NaN if `self` is a negative number other than `-0.0`.
-    ///
-    /// # Precision
-    ///
-    /// The result of this operation is guaranteed to be the rounded
-    /// infinite-precision result. It is specified by IEEE 754 as `squareRoot`
-    /// and guaranteed not to change.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// #![feature(f128)]
-    /// # #[cfg(reliable_f128_math)] {
-    ///
-    /// let positive = 4.0_f128;
-    /// let negative = -4.0_f128;
-    /// let negative_zero = -0.0_f128;
-    ///
-    /// assert_eq!(positive.sqrt(), 2.0);
-    /// assert!(negative.sqrt().is_nan());
-    /// assert!(negative_zero.sqrt() == negative_zero);
-    /// # }
-    /// ```
-    #[inline]
-    #[doc(alias = "squareRoot")]
-    #[rustc_allow_incoherent_impl]
-    #[unstable(feature = "f128", issue = "116909")]
-    #[must_use = "method returns a new number and does not mutate the original value"]
-    pub fn sqrt(self) -> f128 {
-        unsafe { intrinsics::sqrtf128(self) }
-    }
-
     /// Returns `e^(self)`, (the exponential function).
     ///
     /// # Unspecified precision

library/coretests/tests/floats/f32.rs

@@ -46,7 +46,7 @@ impl f32 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn floor(self) -> f32 {
-        unsafe { intrinsics::floorf32(self) }
+        core::f32::floor(self)
     }
 
     /// Returns the smallest integer greater than or equal to `self`.
@@ -68,7 +68,7 @@ impl f32 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn ceil(self) -> f32 {
-        unsafe { intrinsics::ceilf32(self) }
+        core::f32::ceil(self)
     }
 
     /// Returns the nearest integer to `self`. If a value is half-way between two
@@ -96,7 +96,7 @@ impl f32 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn round(self) -> f32 {
-        unsafe { intrinsics::roundf32(self) }
+        core::f32::round(self)
     }
 
     /// Returns the nearest integer to a number. Rounds half-way cases to the number
@@ -122,7 +122,7 @@ impl f32 {
     #[stable(feature = "round_ties_even", since = "1.77.0")]
     #[inline]
     pub fn round_ties_even(self) -> f32 {
-        intrinsics::round_ties_even_f32(self)
+        core::f32::round_ties_even(self)
     }
 
     /// Returns the integer part of `self`.
@@ -147,7 +147,7 @@ impl f32 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn trunc(self) -> f32 {
-        unsafe { intrinsics::truncf32(self) }
+        core::f32::trunc(self)
     }
 
     /// Returns the fractional part of `self`.
@@ -170,7 +170,7 @@ impl f32 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn fract(self) -> f32 {
-        self - self.trunc()
+        core::f32::fract(self)
     }
 
     /// Fused multiply-add. Computes `(self * a) + b` with only one rounding
@@ -212,7 +212,7 @@ impl f32 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn mul_add(self, a: f32, b: f32) -> f32 {
-        unsafe { intrinsics::fmaf32(self, a, b) }
+        core::f32::mul_add(self, a, b)
     }
 
     /// Calculates Euclidean division, the matching method for `rem_euclid`.
@@ -242,11 +242,7 @@ impl f32 {
     #[inline]
     #[stable(feature = "euclidean_division", since = "1.38.0")]
     pub fn div_euclid(self, rhs: f32) -> f32 {
-        let q = (self / rhs).trunc();
-        if self % rhs < 0.0 {
-            return if rhs > 0.0 { q - 1.0 } else { q + 1.0 };
-        }
-        q
+        core::f32::div_euclid(self, rhs)
     }
 
     /// Calculates the least nonnegative remainder of `self (mod rhs)`.
@@ -283,8 +279,7 @@ impl f32 {
     #[inline]
     #[stable(feature = "euclidean_division", since = "1.38.0")]
     pub fn rem_euclid(self, rhs: f32) -> f32 {
-        let r = self % rhs;
-        if r < 0.0 { r + rhs.abs() } else { r }
+        core::f32::rem_euclid(self, rhs)
     }
 
     /// Raises a number to an integer power.
@@ -312,7 +307,7 @@ impl f32 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn powi(self, n: i32) -> f32 {
-        unsafe { intrinsics::powif32(self, n) }
+        core::f32::powi(self, n)
     }
 
     /// Raises a number to a floating point power.
@@ -367,7 +362,7 @@ impl f32 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn sqrt(self) -> f32 {
-        unsafe { intrinsics::sqrtf32(self) }
+        core::f32::sqrt(self)
     }
 
     /// Returns `e^(self)`, (the exponential function).
@@ -567,7 +562,8 @@ impl f32 {
                 filing an issue describing your use-case too)."
     )]
     pub fn abs_sub(self, other: f32) -> f32 {
-        unsafe { cmath::fdimf(self, other) }
+        #[allow(deprecated)]
+        core::f32::abs_sub(self, other)
     }
 
     /// Returns the cube root of a number.
@@ -594,7 +590,7 @@ impl f32 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn cbrt(self) -> f32 {
-        unsafe { cmath::cbrtf(self) }
+        core::f32::cbrt(self)
     }
 
     /// Compute the distance between the origin and a point (`x`, `y`) on the

library/coretests/tests/floats/f64.rs

@@ -46,7 +46,7 @@ impl f64 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn floor(self) -> f64 {
-        unsafe { intrinsics::floorf64(self) }
+        core::f64::floor(self)
     }
 
     /// Returns the smallest integer greater than or equal to `self`.
@@ -68,7 +68,7 @@ impl f64 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn ceil(self) -> f64 {
-        unsafe { intrinsics::ceilf64(self) }
+        core::f64::ceil(self)
     }
 
     /// Returns the nearest integer to `self`. If a value is half-way between two
@@ -96,7 +96,7 @@ impl f64 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn round(self) -> f64 {
-        unsafe { intrinsics::roundf64(self) }
+        core::f64::round(self)
     }
 
     /// Returns the nearest integer to a number. Rounds half-way cases to the number
@@ -122,7 +122,7 @@ impl f64 {
     #[stable(feature = "round_ties_even", since = "1.77.0")]
     #[inline]
     pub fn round_ties_even(self) -> f64 {
-        intrinsics::round_ties_even_f64(self)
+        core::f64::round_ties_even(self)
     }
 
     /// Returns the integer part of `self`.
@@ -147,7 +147,7 @@ impl f64 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn trunc(self) -> f64 {
-        unsafe { intrinsics::truncf64(self) }
+        core::f64::trunc(self)
     }
 
     /// Returns the fractional part of `self`.
@@ -170,7 +170,7 @@ impl f64 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn fract(self) -> f64 {
-        self - self.trunc()
+        core::f64::fract(self)
     }
 
     /// Fused multiply-add. Computes `(self * a) + b` with only one rounding
@@ -212,7 +212,7 @@ impl f64 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn mul_add(self, a: f64, b: f64) -> f64 {
-        unsafe { intrinsics::fmaf64(self, a, b) }
+        core::f64::mul_add(self, a, b)
     }
 
     /// Calculates Euclidean division, the matching method for `rem_euclid`.
@@ -242,11 +242,7 @@ impl f64 {
     #[inline]
     #[stable(feature = "euclidean_division", since = "1.38.0")]
     pub fn div_euclid(self, rhs: f64) -> f64 {
-        let q = (self / rhs).trunc();
-        if self % rhs < 0.0 {
-            return if rhs > 0.0 { q - 1.0 } else { q + 1.0 };
-        }
-        q
+        core::f64::div_euclid(self, rhs)
     }
 
     /// Calculates the least nonnegative remainder of `self (mod rhs)`.
@@ -283,8 +279,7 @@ impl f64 {
     #[inline]
     #[stable(feature = "euclidean_division", since = "1.38.0")]
     pub fn rem_euclid(self, rhs: f64) -> f64 {
-        let r = self % rhs;
-        if r < 0.0 { r + rhs.abs() } else { r }
+        core::f64::rem_euclid(self, rhs)
     }
 
     /// Raises a number to an integer power.
@@ -312,7 +307,7 @@ impl f64 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn powi(self, n: i32) -> f64 {
-        unsafe { intrinsics::powif64(self, n) }
+        core::f64::powi(self, n)
     }
 
     /// Raises a number to a floating point power.
@@ -367,7 +362,7 @@ impl f64 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn sqrt(self) -> f64 {
-        unsafe { intrinsics::sqrtf64(self) }
+        core::f64::sqrt(self)
     }
 
     /// Returns `e^(self)`, (the exponential function).
@@ -567,7 +562,8 @@ impl f64 {
                 filing an issue describing your use-case too)."
     )]
     pub fn abs_sub(self, other: f64) -> f64 {
-        unsafe { cmath::fdim(self, other) }
+        #[allow(deprecated)]
+        core::f64::abs_sub(self, other)
     }
 
     /// Returns the cube root of a number.
@@ -594,7 +590,7 @@ impl f64 {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn cbrt(self) -> f64 {
-        unsafe { cmath::cbrt(self) }
+        core::f64::cbrt(self)
     }
 
     /// Compute the distance between the origin and a point (`x`, `y`) on the

library/coretests/tests/floats/mod.rs

@@ -285,6 +285,7 @@
 #![feature(cfi_encoding)]
 #![feature(char_max_len)]
 #![feature(concat_idents)]
+#![feature(core_float_math)]
 #![feature(decl_macro)]
 #![feature(deprecated_suggestion)]
 #![feature(doc_cfg)]

library/coretests/tests/lib.rs

@@ -7,13 +7,9 @@ unsafe extern "C" {
     pub fn asin(n: f64) -> f64;
     pub fn atan(n: f64) -> f64;
     pub fn atan2(a: f64, b: f64) -> f64;
-    pub fn cbrt(n: f64) -> f64;
-    pub fn cbrtf(n: f32) -> f32;
     pub fn cosh(n: f64) -> f64;
     pub fn expm1(n: f64) -> f64;
     pub fn expm1f(n: f32) -> f32;
-    pub fn fdim(a: f64, b: f64) -> f64;
-    pub fn fdimf(a: f32, b: f32) -> f32;
     #[cfg_attr(target_env = "msvc", link_name = "_hypot")]
     pub fn hypot(x: f64, y: f64) -> f64;
     #[cfg_attr(target_env = "msvc", link_name = "_hypotf")]