diff --git a/geometry/src/basic/line_segment.rs b/geometry/src/basic/line_segment.rs
index 33ba7f04..3d68f655 100644
--- a/geometry/src/basic/line_segment.rs
+++ b/geometry/src/basic/line_segment.rs
@@ -220,17 +220,6 @@ impl LineSegment2F {
         dx * dx + dy * dy
     }
 
-    // Given a line equation of the form `ax + by + c = 0`, returns a vector of the form
-    // `[a, b, c, 0]`.
-    //
-    // TODO(pcwalton): Optimize.
-    #[inline]
-    pub fn line_coords(&self) -> F32x4 {
-        let from = F32x4::new(self.0[0], self.0[1], 1.0, 0.0);
-        let to = F32x4::new(self.0[2], self.0[3], 1.0, 0.0);
-        from.cross(to)
-    }
-
     #[inline]
     pub fn vector(&self) -> Vector2F {
         self.to() - self.from()
diff --git a/simd/src/arm/mod.rs b/simd/src/arm/mod.rs
index 14871608..f73c7303 100644
--- a/simd/src/arm/mod.rs
+++ b/simd/src/arm/mod.rs
@@ -130,11 +130,6 @@ impl F32x4 {
     pub fn concat_wz_yx(self, other: F32x4) -> F32x4 {
         unsafe { F32x4(simd_shuffle4(self.0, other.0, [3, 2, 5, 4])) }
     }
-
-    #[inline]
-    pub fn cross(&self, other: F32x4) -> F32x4 {
-        unimplemented!()
-    }
 }
 
 impl Default for F32x4 {
diff --git a/simd/src/x86/mod.rs b/simd/src/x86/mod.rs
index c4af9a93..d10e1230 100644
--- a/simd/src/x86/mod.rs
+++ b/simd/src/x86/mod.rs
@@ -162,12 +162,6 @@ impl F32x4 {
     pub fn concat_wz_yx(self, other: F32x4) -> F32x4 {
         unsafe { F32x4(x86_64::_mm_shuffle_ps(self.0, other.0, 0b0001_1011)) }
     }
-
-    // FIXME(pcwalton): Move to `Vector4F`!
-    #[inline]
-    pub fn cross(&self, other: F32x4) -> F32x4 {
-        self.yzxw() * other.zxyw() - self.zxyw() * other.yzxw()
-    }
 }
 
 impl Default for F32x4 {