diff --git a/library/compiler-builtins/libm/src/lib.rs b/library/compiler-builtins/libm/src/lib.rs
index 4d7cec56f9df..fc9628d919f3 100644
--- a/library/compiler-builtins/libm/src/lib.rs
+++ b/library/compiler-builtins/libm/src/lib.rs
@@ -1,8 +1,22 @@
+//! Port of MUSL's libm to Rust
+//!
+//! # Usage
+//!
+//! You can use this crate in two ways:
+//!
+//! - By directly using its free functions, e.g. `libm::powf`.
+//!
+//! - By importing the `F32Ext` and / or `F64Ext` extension traits to add methods like `powf` to the
+//! `f32` and `f64` types. Then you'll be able to invoke math functions as methods, e.g. `x.sqrt()`.
+
 #![deny(warnings)]
 #![no_std]
 
 mod math;
 
+#[cfg(todo)]
+use core::{f32, f64};
+
 pub use math::*;
 
 /// Approximate equality with 1 ULP of tolerance
@@ -15,3 +29,679 @@ pub fn _eqf(a: u32, b: u32) -> bool {
 pub fn _eq(a: u64, b: u64) -> bool {
     (a as i64).wrapping_sub(b as i64).abs() <= 1
 }
+
+/// Math support for `f32`
+///
+/// NOTE this meant to be a closed extension trait. The only stable way to use this trait is to
+/// import it to access its methods.
+pub trait F32Ext {
+    #[cfg(todo)]
+    fn floor(self) -> Self;
+
+    #[cfg(todo)]
+    fn ceil(self) -> Self;
+
+    #[cfg(todo)]
+    fn round(self) -> Self;
+
+    #[cfg(todo)]
+    fn trunc(self) -> Self;
+
+    #[cfg(todo)]
+    fn fract(self) -> Self;
+
+    fn abs(self) -> Self;
+
+    #[cfg(todo)]
+    fn signum(self) -> Self;
+
+    #[cfg(todo)]
+    fn mul_add(self, a: Self, b: Self) -> Self;
+
+    #[cfg(todo)]
+    fn div_euc(self, rhs: Self) -> Self;
+
+    #[cfg(todo)]
+    fn mod_euc(self, rhs: Self) -> Self;
+
+    // NOTE depends on unstable intrinsics::powif32
+    // fn powi(self, n: i32) -> Self;
+
+    fn powf(self, n: Self) -> Self;
+
+    fn sqrt(self) -> Self;
+
+    #[cfg(todo)]
+    fn exp(self) -> Self;
+
+    #[cfg(todo)]
+    fn exp2(self) -> Self;
+
+    #[cfg(todo)]
+    fn ln(self) -> Self;
+
+    #[cfg(todo)]
+    fn log(self, base: Self) -> Self;
+
+    #[cfg(todo)]
+    fn log2(self) -> Self;
+
+    #[cfg(todo)]
+    fn log10(self) -> Self;
+
+    #[cfg(todo)]
+    fn cbrt(self) -> Self;
+
+    #[cfg(todo)]
+    fn hypot(self, other: Self) -> Self;
+
+    #[cfg(todo)]
+    fn sin(self) -> Self;
+
+    #[cfg(todo)]
+    fn cos(self) -> Self;
+
+    #[cfg(todo)]
+    fn tan(self) -> Self;
+
+    #[cfg(todo)]
+    fn asin(self) -> Self;
+
+    #[cfg(todo)]
+    fn acos(self) -> Self;
+
+    #[cfg(todo)]
+    fn atan(self) -> Self;
+
+    #[cfg(todo)]
+    fn atan2(self, other: Self) -> Self;
+
+    #[cfg(todo)]
+    #[inline]
+    fn sin_cos(self) -> (Self, Self) {
+        (self.sin(), self.cos())
+    }
+
+    #[cfg(todo)]
+    fn exp_m1(self) -> Self;
+
+    #[cfg(todo)]
+    fn ln_1p(self) -> Self;
+
+    #[cfg(todo)]
+    fn sinh(self) -> Self;
+
+    #[cfg(todo)]
+    fn cosh(self) -> Self;
+
+    #[cfg(todo)]
+    fn tanh(self) -> Self;
+
+    #[cfg(todo)]
+    fn asinh(self) -> Self;
+
+    #[cfg(todo)]
+    fn acosh(self) -> Self;
+
+    #[cfg(todo)]
+    fn atanh(self) -> Self;
+}
+
+impl F32Ext for f32 {
+    #[cfg(todo)]
+    #[inline]
+    fn floor(self) -> Self {
+        floorf(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn ceil(self) -> Self {
+        ceilf(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn round(self) -> Self {
+        roundf(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn trunc(self) -> Self {
+        truncf(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn fract(self) -> Self {
+        self - self.trunc()
+    }
+
+    #[inline]
+    fn abs(self) -> Self {
+        fabsf(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn mul_add(self, a: Self, b: Self) -> Self {
+        fmaf(self, a, b)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn div_euc(self, rhs: Self) -> Self {
+        let q = (self / rhs).trunc();
+        if self % rhs < 0.0 {
+            return if rhs > 0.0 { q - 1.0 } else { q + 1.0 };
+        }
+        q
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn mod_euc(self, rhs: f32) -> f32 {
+        let r = self % rhs;
+        if r < 0.0 {
+            r + rhs.abs()
+        } else {
+            r
+        }
+    }
+
+    #[inline]
+    fn powf(self, n: Self) -> Self {
+        powf(self, n)
+    }
+
+    #[inline]
+    fn sqrt(self) -> Self {
+        sqrtf(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn exp(self) -> Self {
+        expf(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn exp2(self) -> Self {
+        exp2f(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn ln(self) -> Self {
+        logf(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn log(self, base: Self) -> Self {
+        self.ln() / base.ln()
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn log2(self) -> Self {
+        log2f(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn log10(self) -> Self {
+        log10f(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn cbrt(self) -> Self {
+        cbrtf(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn hypot(self, other: Self) -> Self {
+        hypotf(self, other)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn sin(self) -> Self {
+        sinf(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn cos(self) -> Self {
+        cosf(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn tan(self) -> Self {
+        tanf(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn asin(self) -> Self {
+        asinf(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn acos(self) -> Self {
+        acosf(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn atan(self) -> Self {
+        atanf(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn atan2(self, other: Self) -> Self {
+        atan2f(self, other)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn exp_m1(self) -> Self {
+        expm1f(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn ln_1p(self) -> Self {
+        log1pf(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn sinh(self) -> Self {
+        sinhf(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn cosh(self) -> Self {
+        coshf(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn tanh(self) -> Self {
+        tanhf(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn asinh(self) -> Self {
+        if self == f32::NEG_INFINITY {
+            f32::NEG_INFINITY
+        } else {
+            (self + ((self * self) + 1.0).sqrt()).ln()
+        }
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn acosh(self) -> Self {
+        match self {
+            x if x < 1.0 => f32::NAN,
+            x => (x + ((x * x) - 1.0).sqrt()).ln(),
+        }
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn atanh(self) -> Self {
+        0.5 * ((2.0 * self) / (1.0 - self)).ln_1p()
+    }
+}
+
+/// Math support for `f32`
+///
+/// NOTE this meant to be a closed extension trait. The only stable way to use this trait is to
+/// import it to access its methods.
+pub trait F64Ext {
+    #[cfg(todo)]
+    fn floor(self) -> Self;
+
+    #[cfg(todo)]
+    fn ceil(self) -> Self;
+
+    #[cfg(todo)]
+    fn round(self) -> Self;
+
+    #[cfg(todo)]
+    fn trunc(self) -> Self;
+
+    #[cfg(todo)]
+    fn fract(self) -> Self;
+
+    fn abs(self) -> Self;
+
+    #[cfg(todo)]
+    fn signum(self) -> Self;
+
+    #[cfg(todo)]
+    fn mul_add(self, a: Self, b: Self) -> Self;
+
+    #[cfg(todo)]
+    fn div_euc(self, rhs: Self) -> Self;
+
+    #[cfg(todo)]
+    fn mod_euc(self, rhs: Self) -> Self;
+
+    // NOTE depends on unstable intrinsics::powif64
+    // fn powi(self, n: i32) -> Self;
+
+    #[cfg(todo)]
+    fn powf(self, n: Self) -> Self;
+
+    #[cfg(todo)]
+    fn sqrt(self) -> Self;
+
+    #[cfg(todo)]
+    fn exp(self) -> Self;
+
+    #[cfg(todo)]
+    fn exp2(self) -> Self;
+
+    #[cfg(todo)]
+    fn ln(self) -> Self;
+
+    #[cfg(todo)]
+    fn log(self, base: Self) -> Self;
+
+    #[cfg(todo)]
+    fn log2(self) -> Self;
+
+    #[cfg(todo)]
+    fn log10(self) -> Self;
+
+    #[cfg(todo)]
+    fn cbrt(self) -> Self;
+
+    #[cfg(todo)]
+    fn hypot(self, other: Self) -> Self;
+
+    #[cfg(todo)]
+    fn sin(self) -> Self;
+
+    #[cfg(todo)]
+    fn cos(self) -> Self;
+
+    #[cfg(todo)]
+    fn tan(self) -> Self;
+
+    #[cfg(todo)]
+    fn asin(self) -> Self;
+
+    #[cfg(todo)]
+    fn acos(self) -> Self;
+
+    #[cfg(todo)]
+    fn atan(self) -> Self;
+
+    #[cfg(todo)]
+    fn atan2(self, other: Self) -> Self;
+
+    #[cfg(todo)]
+    #[inline]
+    fn sin_cos(self) -> (Self, Self) {
+        (self.sin(), self.cos())
+    }
+
+    #[cfg(todo)]
+    fn exp_m1(self) -> Self;
+
+    #[cfg(todo)]
+    fn ln_1p(self) -> Self;
+
+    #[cfg(todo)]
+    fn sinh(self) -> Self;
+
+    #[cfg(todo)]
+    fn cosh(self) -> Self;
+
+    #[cfg(todo)]
+    fn tanh(self) -> Self;
+
+    #[cfg(todo)]
+    fn asinh(self) -> Self;
+
+    #[cfg(todo)]
+    fn acosh(self) -> Self;
+
+    #[cfg(todo)]
+    fn atanh(self) -> Self;
+}
+
+impl F64Ext for f64 {
+    #[cfg(todo)]
+    #[inline]
+    fn floor(self) -> Self {
+        floor(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn ceil(self) -> Self {
+        ceil(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn round(self) -> Self {
+        round(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn trunc(self) -> Self {
+        trunc(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn fract(self) -> Self {
+        self - self.trunc()
+    }
+
+    #[inline]
+    fn abs(self) -> Self {
+        fabs(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn mul_add(self, a: Self, b: Self) -> Self {
+        fma(self, a, b)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn div_euc(self, rhs: Self) -> Self {
+        let q = (self / rhs).trunc();
+        if self % rhs < 0.0 {
+            return if rhs > 0.0 { q - 1.0 } else { q + 1.0 };
+        }
+        q
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn mod_euc(self, rhs: f32) -> f32 {
+        let r = self % rhs;
+        if r < 0.0 {
+            r + rhs.abs()
+        } else {
+            r
+        }
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn powf(self, n: Self) -> Self {
+        pow(self, n)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn sqrt(self) -> Self {
+        sqrt(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn exp(self) -> Self {
+        exp(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn exp2(self) -> Self {
+        exp2(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn ln(self) -> Self {
+        log(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn log(self, base: Self) -> Self {
+        self.ln() / base.ln()
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn log2(self) -> Self {
+        log2(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn log10(self) -> Self {
+        log10(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn cbrt(self) -> Self {
+        cbrt(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn hypot(self, other: Self) -> Self {
+        hypot(self, other)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn sin(self) -> Self {
+        sin(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn cos(self) -> Self {
+        cos(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn tan(self) -> Self {
+        tan(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn asin(self) -> Self {
+        asin(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn acos(self) -> Self {
+        acos(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn atan(self) -> Self {
+        atan(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn atan2(self, other: Self) -> Self {
+        atan2(self, other)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn exp_m1(self) -> Self {
+        expm1(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn ln_1p(self) -> Self {
+        log1p(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn sinh(self) -> Self {
+        sinh(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn cosh(self) -> Self {
+        cosh(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn tanh(self) -> Self {
+        tanh(self)
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn asinh(self) -> Self {
+        if self == f64::NEG_INFINITY {
+            f64::NEG_INFINITY
+        } else {
+            (self + ((self * self) + 1.0).sqrt()).ln()
+        }
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn acosh(self) -> Self {
+        match self {
+            x if x < 1.0 => f64::NAN,
+            x => (x + ((x * x) - 1.0).sqrt()).ln(),
+        }
+    }
+
+    #[cfg(todo)]
+    #[inline]
+    fn atanh(self) -> Self {
+        0.5 * ((2.0 * self) / (1.0 - self)).ln_1p()
+    }
+}