diff --git a/library/std/src/sys/cmath.rs b/library/std/src/sys/cmath.rs
new file mode 100644
index 0000000000000..99df503b82de2
--- /dev/null
+++ b/library/std/src/sys/cmath.rs
@@ -0,0 +1,88 @@
+#![cfg(not(test))]
+
+// These symbols are all defined by `libm`,
+// or by `compiler-builtins` on unsupported platforms.
+extern "C" {
+    pub fn acos(n: f64) -> f64;
+    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")]
+    pub fn hypotf(x: f32, y: f32) -> f32;
+    pub fn log1p(n: f64) -> f64;
+    pub fn log1pf(n: f32) -> f32;
+    pub fn sinh(n: f64) -> f64;
+    pub fn tan(n: f64) -> f64;
+    pub fn tanh(n: f64) -> f64;
+    pub fn tgamma(n: f64) -> f64;
+    pub fn tgammaf(n: f32) -> f32;
+    pub fn lgamma_r(n: f64, s: &mut i32) -> f64;
+    pub fn lgammaf_r(n: f32, s: &mut i32) -> f32;
+
+    cfg_if::cfg_if! {
+    if #[cfg(not(all(target_os = "windows", target_env = "msvc", target_arch = "x86")))] {
+        pub fn acosf(n: f32) -> f32;
+        pub fn asinf(n: f32) -> f32;
+        pub fn atan2f(a: f32, b: f32) -> f32;
+        pub fn atanf(n: f32) -> f32;
+        pub fn coshf(n: f32) -> f32;
+        pub fn sinhf(n: f32) -> f32;
+        pub fn tanf(n: f32) -> f32;
+        pub fn tanhf(n: f32) -> f32;
+    }}
+}
+
+// On 32-bit x86 MSVC these functions aren't defined, so we just define shims
+// which promote everything to f64, perform the calculation, and then demote
+// back to f32. While not precisely correct should be "correct enough" for now.
+cfg_if::cfg_if! {
+if #[cfg(all(target_os = "windows", target_env = "msvc", target_arch = "x86"))] {
+    #[inline]
+    pub unsafe fn acosf(n: f32) -> f32 {
+        f64::acos(n as f64) as f32
+    }
+
+    #[inline]
+    pub unsafe fn asinf(n: f32) -> f32 {
+        f64::asin(n as f64) as f32
+    }
+
+    #[inline]
+    pub unsafe fn atan2f(n: f32, b: f32) -> f32 {
+        f64::atan2(n as f64, b as f64) as f32
+    }
+
+    #[inline]
+    pub unsafe fn atanf(n: f32) -> f32 {
+        f64::atan(n as f64) as f32
+    }
+
+    #[inline]
+    pub unsafe fn coshf(n: f32) -> f32 {
+        f64::cosh(n as f64) as f32
+    }
+
+    #[inline]
+    pub unsafe fn sinhf(n: f32) -> f32 {
+        f64::sinh(n as f64) as f32
+    }
+
+    #[inline]
+    pub unsafe fn tanf(n: f32) -> f32 {
+        f64::tan(n as f64) as f32
+    }
+
+    #[inline]
+    pub unsafe fn tanhf(n: f32) -> f32 {
+        f64::tanh(n as f64) as f32
+    }
+}}
diff --git a/library/std/src/sys/cmath/builtins.rs b/library/std/src/sys/cmath/builtins.rs
deleted file mode 100644
index c680132efa4ba..0000000000000
--- a/library/std/src/sys/cmath/builtins.rs
+++ /dev/null
@@ -1,35 +0,0 @@
-// These symbols are all defined by `libm`,
-// or by `compiler-builtins` on unsupported platforms.
-
-extern "C" {
-    pub fn acos(n: f64) -> f64;
-    pub fn acosf(n: f32) -> f32;
-    pub fn asin(n: f64) -> f64;
-    pub fn asinf(n: f32) -> f32;
-    pub fn atan(n: f64) -> f64;
-    pub fn atan2(a: f64, b: f64) -> f64;
-    pub fn atan2f(a: f32, b: f32) -> f32;
-    pub fn atanf(n: f32) -> f32;
-    pub fn cbrt(n: f64) -> f64;
-    pub fn cbrtf(n: f32) -> f32;
-    pub fn cosh(n: f64) -> f64;
-    pub fn coshf(n: f32) -> f32;
-    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;
-    pub fn hypot(x: f64, y: f64) -> f64;
-    pub fn hypotf(x: f32, y: f32) -> f32;
-    pub fn log1p(n: f64) -> f64;
-    pub fn log1pf(n: f32) -> f32;
-    pub fn sinh(n: f64) -> f64;
-    pub fn sinhf(n: f32) -> f32;
-    pub fn tan(n: f64) -> f64;
-    pub fn tanf(n: f32) -> f32;
-    pub fn tanh(n: f64) -> f64;
-    pub fn tanhf(n: f32) -> f32;
-    pub fn tgamma(n: f64) -> f64;
-    pub fn tgammaf(n: f32) -> f32;
-    pub fn lgamma_r(n: f64, s: &mut i32) -> f64;
-    pub fn lgammaf_r(n: f32, s: &mut i32) -> f32;
-}
diff --git a/library/std/src/sys/cmath/mod.rs b/library/std/src/sys/cmath/mod.rs
deleted file mode 100644
index 79d5021dd8dc3..0000000000000
--- a/library/std/src/sys/cmath/mod.rs
+++ /dev/null
@@ -1,11 +0,0 @@
-#![cfg(not(test))]
-
-cfg_if::cfg_if! {
-    if #[cfg(target_os = "windows")] {
-        mod windows;
-        pub use windows::*;
-    } else {
-        mod builtins;
-        pub use builtins::*;
-    }
-}
diff --git a/library/std/src/sys/cmath/windows.rs b/library/std/src/sys/cmath/windows.rs
deleted file mode 100644
index 712097f06ff30..0000000000000
--- a/library/std/src/sys/cmath/windows.rs
+++ /dev/null
@@ -1,94 +0,0 @@
-use core::ffi::{c_double, c_float, c_int};
-
-extern "C" {
-    pub fn acos(n: c_double) -> c_double;
-    pub fn asin(n: c_double) -> c_double;
-    pub fn atan(n: c_double) -> c_double;
-    pub fn atan2(a: c_double, b: c_double) -> c_double;
-    pub fn cbrt(n: c_double) -> c_double;
-    pub fn cbrtf(n: c_float) -> c_float;
-    pub fn cosh(n: c_double) -> c_double;
-    pub fn expm1(n: c_double) -> c_double;
-    pub fn expm1f(n: c_float) -> c_float;
-    pub fn fdim(a: c_double, b: c_double) -> c_double;
-    pub fn fdimf(a: c_float, b: c_float) -> c_float;
-    #[cfg_attr(target_env = "msvc", link_name = "_hypot")]
-    pub fn hypot(x: c_double, y: c_double) -> c_double;
-    #[cfg_attr(target_env = "msvc", link_name = "_hypotf")]
-    pub fn hypotf(x: c_float, y: c_float) -> c_float;
-    pub fn log1p(n: c_double) -> c_double;
-    pub fn log1pf(n: c_float) -> c_float;
-    pub fn sinh(n: c_double) -> c_double;
-    pub fn tan(n: c_double) -> c_double;
-    pub fn tanh(n: c_double) -> c_double;
-    pub fn tgamma(n: c_double) -> c_double;
-    pub fn tgammaf(n: c_float) -> c_float;
-    pub fn lgamma_r(n: c_double, s: &mut c_int) -> c_double;
-    pub fn lgammaf_r(n: c_float, s: &mut c_int) -> c_float;
-}
-
-pub use self::shims::*;
-
-#[cfg(not(all(target_env = "msvc", target_arch = "x86")))]
-mod shims {
-    use core::ffi::c_float;
-
-    extern "C" {
-        pub fn acosf(n: c_float) -> c_float;
-        pub fn asinf(n: c_float) -> c_float;
-        pub fn atan2f(a: c_float, b: c_float) -> c_float;
-        pub fn atanf(n: c_float) -> c_float;
-        pub fn coshf(n: c_float) -> c_float;
-        pub fn sinhf(n: c_float) -> c_float;
-        pub fn tanf(n: c_float) -> c_float;
-        pub fn tanhf(n: c_float) -> c_float;
-    }
-}
-
-// On 32-bit x86 MSVC these functions aren't defined, so we just define shims
-// which promote everything to f64, perform the calculation, and then demote
-// back to f32. While not precisely correct should be "correct enough" for now.
-#[cfg(all(target_env = "msvc", target_arch = "x86"))]
-mod shims {
-    use core::ffi::c_float;
-
-    #[inline]
-    pub unsafe fn acosf(n: c_float) -> c_float {
-        f64::acos(n as f64) as c_float
-    }
-
-    #[inline]
-    pub unsafe fn asinf(n: c_float) -> c_float {
-        f64::asin(n as f64) as c_float
-    }
-
-    #[inline]
-    pub unsafe fn atan2f(n: c_float, b: c_float) -> c_float {
-        f64::atan2(n as f64, b as f64) as c_float
-    }
-
-    #[inline]
-    pub unsafe fn atanf(n: c_float) -> c_float {
-        f64::atan(n as f64) as c_float
-    }
-
-    #[inline]
-    pub unsafe fn coshf(n: c_float) -> c_float {
-        f64::cosh(n as f64) as c_float
-    }
-
-    #[inline]
-    pub unsafe fn sinhf(n: c_float) -> c_float {
-        f64::sinh(n as f64) as c_float
-    }
-
-    #[inline]
-    pub unsafe fn tanf(n: c_float) -> c_float {
-        f64::tan(n as f64) as c_float
-    }
-
-    #[inline]
-    pub unsafe fn tanhf(n: c_float) -> c_float {
-        f64::tanh(n as f64) as c_float
-    }
-}