add cast kind of from_exposed_addr (int-to-ptr casts)

[rust.git] / compiler / rustc_const_eval / src / transform / promote_consts.rs

diff --git a/compiler/rustc_const_eval/src/transform/promote_consts.rs b/compiler/rustc_const_eval/src/transform/promote_consts.rs
index fc6b8a1a7234c917acfd8592ee349a3b97f03a5a..4879e8de10000f4f2ee44eefff13419bba0a5a69 100644 (file)
--- 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_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 +501,12 @@ fn validate_rvalue(&mut self, rvalue: &Rvalue<'tcx>) -> Result<(), Unpromotable>
 
             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::PointerExposeAddress, _, _) => return Err(Unpromotable),
 
+            // all ohter casts including int-to-ptr casts are fine, they just use the integer value
+            // at pointer type.
+            Rvalue::Cast(_, operand, _) => {
                 self.validate_operand(operand)?;
             }