Add a pointer to address cast kind

A pointer to address cast are often special-cased.
Introduce a dedicated cast kind to make them easy distinguishable.

2 files changed, 8 insertions, 21 deletions

diff --git a/compiler/rustc_const_eval/src/transform/check_consts/check.rs b/compiler/rustc_const_eval/src/transform/check_consts/check.rs
index eea6e2a47a9..4ef33d62a6b 100644
--- a/compiler/rustc_const_eval/src/transform/check_consts/check.rs
+++ b/compiler/rustc_const_eval/src/transform/check_consts/check.rs
@@ -8,7 +8,6 @@ use rustc_infer::infer::TyCtxtInferExt;
 use rustc_infer::traits::{ImplSource, Obligation, ObligationCause};
 use rustc_middle::mir::visit::{MutatingUseContext, NonMutatingUseContext, PlaceContext, Visitor};
 use rustc_middle::mir::*;
-use rustc_middle::ty::cast::CastTy;
 use rustc_middle::ty::subst::{GenericArgKind, InternalSubsts};
 use rustc_middle::ty::{self, adjustment::PointerCast, Instance, InstanceDef, Ty, TyCtxt};
 use rustc_middle::ty::{Binder, TraitPredicate, TraitRef, TypeFoldable};
@@ -543,16 +542,12 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
                 // in the type of any local, which also excludes casts).
             }
 
-            Rvalue::Cast(CastKind::Misc, ref operand, cast_ty) => {
-                let operand_ty = operand.ty(self.body, self.tcx);
-                let cast_in = CastTy::from_ty(operand_ty).expect("bad input type for cast");
-                let cast_out = CastTy::from_ty(cast_ty).expect("bad output type for cast");
-
-                if let (CastTy::Ptr(_) | CastTy::FnPtr, CastTy::Int(_)) = (cast_in, cast_out) {
-                    self.check_op(ops::RawPtrToIntCast);
-                }
+            Rvalue::Cast(CastKind::PointerAddress, _, _) => {
+                self.check_op(ops::RawPtrToIntCast);
             }
 
+            Rvalue::Cast(CastKind::Misc, _, _) => {}
+
             Rvalue::NullaryOp(NullOp::SizeOf | NullOp::AlignOf, _) => {}
             Rvalue::ShallowInitBox(_, _) => {}
 
diff --git a/compiler/rustc_const_eval/src/transform/promote_consts.rs b/compiler/rustc_const_eval/src/transform/promote_consts.rs
index fc6b8a1a723..ea23bd14d25 100644
--- a/compiler/rustc_const_eval/src/transform/promote_consts.rs
+++ b/compiler/rustc_const_eval/src/transform/promote_consts.rs
@@ -16,7 +16,6 @@ use rustc_hir as hir;
 use rustc_middle::mir::traversal::ReversePostorderIter;
 use rustc_middle::mir::visit::{MutVisitor, MutatingUseContext, PlaceContext, Visitor};
 use rustc_middle::mir::*;
-use rustc_middle::ty::cast::CastTy;
 use rustc_middle::ty::subst::InternalSubsts;
 use rustc_middle::ty::{self, List, TyCtxt, TypeFoldable};
 use rustc_span::Span;
@@ -502,18 +501,11 @@ impl<'tcx> Validator<'_, 'tcx> {
 
             Rvalue::ThreadLocalRef(_) => return Err(Unpromotable),
 
-            Rvalue::Cast(kind, operand, cast_ty) => {
-                if matches!(kind, CastKind::Misc) {
-                    let operand_ty = operand.ty(self.body, self.tcx);
-                    let cast_in = CastTy::from_ty(operand_ty).expect("bad input type for cast");
-                    let cast_out = CastTy::from_ty(*cast_ty).expect("bad output type for cast");
-                    if let (CastTy::Ptr(_) | CastTy::FnPtr, CastTy::Int(_)) = (cast_in, cast_out) {
-                        // ptr-to-int casts are not possible in consts and thus not promotable
-                        return Err(Unpromotable);
-                    }
-                    // int-to-ptr casts are fine, they just use the integer value at pointer type.
-                }
+            // ptr-to-int casts are not possible in consts and thus not promotable
+            Rvalue::Cast(CastKind::PointerAddress, _, _) => return Err(Unpromotable),
 
+            // int-to-ptr casts are fine, they just use the integer value at pointer type.
+            Rvalue::Cast(_, operand, _) => {
                 self.validate_operand(operand)?;
             }