Auto merge of #117525 - GKFX:remove_option_payload_ptr, r=petrochenkov

Remove option_payload_ptr; redundant to offset_of

The `option_payload_ptr` intrinsic is no longer required as `offset_of` supports traversing enums (#114208). This PR removes it in order to dogfood offset_of (as suggested at https://github.com/rust-lang/rust/issues/106655#issuecomment-1790907626). However, it will not build until those changes reach beta (which I think is within the next 8 days?) so I've opened it as a draft.

3 files changed, 0 insertions, 52 deletions

diff --git a/compiler/rustc_hir_analysis/src/check/intrinsic.rs b/compiler/rustc_hir_analysis/src/check/intrinsic.rs
index eb009b9368f..7ea21b24fc8 100644
--- a/compiler/rustc_hir_analysis/src/check/intrinsic.rs
+++ b/compiler/rustc_hir_analysis/src/check/intrinsic.rs
@@ -225,25 +225,6 @@ pub fn check_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>) {
                 ],
                 Ty::new_ptr(tcx, ty::TypeAndMut { ty: param(0), mutbl: hir::Mutability::Not }),
             ),
-            sym::option_payload_ptr => {
-                let option_def_id = tcx.require_lang_item(hir::LangItem::Option, None);
-                let p0 = param(0);
-                (
-                    1,
-                    vec![Ty::new_ptr(
-                        tcx,
-                        ty::TypeAndMut {
-                            ty: Ty::new_adt(
-                                tcx,
-                                tcx.adt_def(option_def_id),
-                                tcx.mk_args_from_iter([ty::GenericArg::from(p0)].into_iter()),
-                            ),
-                            mutbl: hir::Mutability::Not,
-                        },
-                    )],
-                    Ty::new_ptr(tcx, ty::TypeAndMut { ty: p0, mutbl: hir::Mutability::Not }),
-                )
-            }
             sym::ptr_mask => (
                 1,
                 vec![
diff --git a/compiler/rustc_mir_transform/src/lower_intrinsics.rs b/compiler/rustc_mir_transform/src/lower_intrinsics.rs
index 5f3d8dfc6c4..249e0fc633e 100644
--- a/compiler/rustc_mir_transform/src/lower_intrinsics.rs
+++ b/compiler/rustc_mir_transform/src/lower_intrinsics.rs
@@ -4,7 +4,6 @@ use crate::MirPass;
 use rustc_middle::mir::*;
 use rustc_middle::ty::{self, TyCtxt};
 use rustc_span::symbol::sym;
-use rustc_target::abi::{FieldIdx, VariantIdx};
 
 pub struct LowerIntrinsics;
 
@@ -251,37 +250,6 @@ impl<'tcx> MirPass<'tcx> for LowerIntrinsics {
                         });
                         terminator.kind = TerminatorKind::Goto { target };
                     }
-                    sym::option_payload_ptr => {
-                        if let (Some(target), Some(arg)) = (*target, args[0].place()) {
-                            let ty::RawPtr(ty::TypeAndMut { ty: dest_ty, .. }) =
-                                destination.ty(local_decls, tcx).ty.kind()
-                            else {
-                                bug!();
-                            };
-
-                            block.statements.push(Statement {
-                                source_info: terminator.source_info,
-                                kind: StatementKind::Assign(Box::new((
-                                    *destination,
-                                    Rvalue::AddressOf(
-                                        Mutability::Not,
-                                        arg.project_deeper(
-                                            &[
-                                                PlaceElem::Deref,
-                                                PlaceElem::Downcast(
-                                                    Some(sym::Some),
-                                                    VariantIdx::from_u32(1),
-                                                ),
-                                                PlaceElem::Field(FieldIdx::from_u32(0), *dest_ty),
-                                            ],
-                                            tcx,
-                                        ),
-                                    ),
-                                ))),
-                            });
-                            terminator.kind = TerminatorKind::Goto { target };
-                        }
-                    }
                     sym::transmute | sym::transmute_unchecked => {
                         let dst_ty = destination.ty(local_decls, tcx).ty;
                         let Ok([arg]) = <[_; 1]>::try_from(std::mem::take(args)) else {
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 302be85a429..2e3b5446405 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -1164,7 +1164,6 @@ symbols! {
         optin_builtin_traits,
         option,
         option_env,
-        option_payload_ptr,
         options,
         or,
         or_patterns,