Allow core_intrinsics when autodiff is enabled

Author: Sa4dUs

compiler/rustc_middle/src/middle/stability.rs

@@ -409,6 +409,12 @@ impl<'tcx> TyCtxt<'tcx> {
                     return EvalResult::Allow;
                 }
 
+                // The `#[autodiff_forward]` and `#[autodiff_reverse]` attribute macros use `enzyme_autodiff` core intrinsic in its expansion.
+                // To avoid requiring users to manually add `#![feature(core_intrinsics)]`, we allow this feature when `autodiff` is enabled.
+                if self.features().enabled(sym::autodiff) && feature == sym::core_intrinsics {
+                    return EvalResult::Allow;
+                }
+
                 let suggestion = suggestion_for_allocator_api(self, def_id, span, feature);
                 EvalResult::Deny {
                     feature,
@@ -555,6 +561,7 @@ impl<'tcx> TyCtxt<'tcx> {
         let is_allowed = matches!(eval_result, EvalResult::Allow);
         match eval_result {
             EvalResult::Allow => {}
+            // MARKER(Sa4dUs): Here
             EvalResult::Deny { feature, reason, issue, suggestion, is_soft } => report_unstable(
                 self.sess,
                 feature,

compiler/rustc_span/src/symbol.rs

@@ -540,6 +540,7 @@ symbols! {
         audit_that,
         augmented_assignments,
         auto_traits,
+        autodiff,
         autodiff_forward,
         autodiff_reverse,
         automatically_derived,
@@ -750,6 +751,7 @@ symbols! {
         copysignf64,
         copysignf128,
         core,
+        core_intrinsics,
         core_panic,
         core_panic_2015_macro,
         core_panic_2021_macro,

tests/codegen-llvm/autodiffv2.rs renamed to tests/codegen-llvm/autodiff/autodiffv2.rs

@@ -25,7 +25,6 @@
 // in our frontend and in the llvm backend to avoid these issues.
 
 #![feature(autodiff)]
-#![feature(core_intrinsics)]
 
 use std::autodiff::autodiff_forward;
 

tests/codegen-llvm/autodiff/batched.rs

@@ -10,7 +10,6 @@
 // reduce this test to only match the first lines and the ret instructions.
 
 #![feature(autodiff)]
-#![feature(core_intrinsics)]
 
 use std::autodiff::autodiff_forward;
 

tests/codegen-llvm/autodiff/generic.rs

@@ -2,7 +2,6 @@
 //@ no-prefer-dynamic
 //@ needs-enzyme
 #![feature(autodiff)]
-#![feature(core_intrinsics)]
 
 use std::autodiff::autodiff_reverse;
 

tests/codegen-llvm/autodiff/identical_fnc.rs

@@ -10,7 +10,6 @@
 // We also explicetly test that we keep running merge_function after AD, by checking for two
 // identical function calls in the LLVM-IR, while having two different calls in the Rust code.
 #![feature(autodiff)]
-#![feature(core_intrinsics)]
 
 use std::autodiff::autodiff_reverse;
 

tests/codegen-llvm/autodiff/scalar.rs

@@ -2,7 +2,6 @@
 //@ no-prefer-dynamic
 //@ needs-enzyme
 #![feature(autodiff)]
-#![feature(core_intrinsics)]
 
 use std::autodiff::autodiff_reverse;
 

tests/codegen-llvm/autodiff/sret.rs

@@ -8,7 +8,6 @@
 // We therefore use this test to verify some of our sret handling.
 
 #![feature(autodiff)]
-#![feature(core_intrinsics)]
 
 use std::autodiff::autodiff_reverse;
 

tests/codegen-llvm/autodiff/trait.rs

@@ -5,7 +5,6 @@
 // Just check it does not crash for now
 // CHECK: ;
 #![feature(autodiff)]
-#![feature(core_intrinsics)]
 
 use std::autodiff::autodiff_reverse;
 

tests/pretty/autodiff/autodiff_forward.pp

@@ -3,7 +3,6 @@
 //@ needs-enzyme
 
 #![feature(autodiff)]
-#![feature(core_intrinsics)]
 #[prelude_import]
 use ::std::prelude::rust_2015::*;
 #[macro_use]