Basic implementation of autodiff intrinsic

Author: Sa4dUs

core/src/intrinsics/mod.rs

@@ -3157,6 +3157,10 @@ pub const unsafe fn copysignf64(x: f64, y: f64) -> f64;
 #[rustc_intrinsic]
 pub const unsafe fn copysignf128(x: f128, y: f128) -> f128;
 
+#[rustc_nounwind]
+#[rustc_intrinsic]
+pub const fn autodiff<F, G, T: crate::marker::Tuple, R>(f: F, df: G, args: T) -> R;
+
 /// Inform Miri that a given pointer definitely has a certain alignment.
 #[cfg(miri)]
 #[rustc_allow_const_fn_unstable(const_eval_select)]