Undo fn -> const fn for all intrinsics but assert_inhabited

Author: usbalbin

compiler/rustc_mir/src/interpret/intrinsics.rs

@@ -407,29 +407,13 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             sym::transmute => {
                 self.copy_op_transmute(args[0], dest)?;
             }
-            sym::assert_inhabited | sym::assert_zero_valid | sym::assert_uninit_valid => {
+            sym::assert_inhabited => {
                 let ty = instance.substs.type_at(0);
                 let layout = self.layout_of(ty)?;
 
                 if layout.abi.is_uninhabited() {
                     throw_ub_format!("attempted to instantiate uninhabited type `{}`", ty);
                 }
-                if intrinsic_name == sym::assert_zero_valid
-                    && !layout.might_permit_raw_init(self, /*zero:*/ true).unwrap()
-                {
-                    throw_ub_format!(
-                        "attempted to zero-initialize type `{}`, which is invalid",
-                        ty
-                    );
-                }
-                if intrinsic_name == sym::assert_uninit_valid
-                    && !layout.might_permit_raw_init(self, /*zero:*/ false).unwrap()
-                {
-                    throw_ub_format!(
-                        "attempted to leave type `{}` uninitialized, which is invalid",
-                        ty
-                    );
-                }
             }
             sym::simd_insert => {
                 let index = u64::from(self.read_scalar(args[1])?.to_u32()?);

library/core/src/intrinsics.rs

@@ -822,14 +822,12 @@ extern "rust-intrinsic" {
     /// zero-initialization: This will statically either panic, or do nothing.
     ///
     /// This intrinsic does not have a stable counterpart.
-    #[rustc_const_unstable(feature = "const_assert_type", issue = "none")]
     pub fn assert_zero_valid<T>();
 
     /// A guard for unsafe functions that cannot ever be executed if `T` has invalid
     /// bit patterns: This will statically either panic, or do nothing.
     ///
     /// This intrinsic does not have a stable counterpart.
-    #[rustc_const_unstable(feature = "const_assert_type", issue = "none")]
     pub fn assert_uninit_valid<T>();
 
     /// Gets a reference to a static `Location` indicating where it was called.