diff --git a/rust-version b/rust-version
index 5f1a4428febc1..e6c238023e407 100644
--- a/rust-version
+++ b/rust-version
@@ -1 +1 @@
-e1c91213ff80af5b87a197b784b40bcbc8cf3add
+a803f313fdf8f6eb2d674d7dfb3694a2b437ee1e
diff --git a/src/machine.rs b/src/machine.rs
index a7a61a1f44c7d..e5a748453e881 100644
--- a/src/machine.rs
+++ b/src/machine.rs
@@ -9,6 +9,7 @@ use rand::rngs::StdRng;
 use rand::SeedableRng;
 
 use rustc_ast::ast::Mutability;
+use rustc_const_eval::const_eval::CheckAlignment;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 #[allow(unused)]
 use rustc_data_structures::static_assert_size;
@@ -22,7 +23,7 @@ use rustc_middle::{
 };
 use rustc_span::def_id::{CrateNum, DefId};
 use rustc_span::Symbol;
-use rustc_target::abi::Size;
+use rustc_target::abi::{Align, Size};
 use rustc_target::spec::abi::Abi;
 
 use crate::{
@@ -781,8 +782,12 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for MiriMachine<'mir, 'tcx> {
     const PANIC_ON_ALLOC_FAIL: bool = false;
 
     #[inline(always)]
-    fn enforce_alignment(ecx: &MiriInterpCx<'mir, 'tcx>) -> bool {
-        ecx.machine.check_alignment != AlignmentCheck::None
+    fn enforce_alignment(ecx: &MiriInterpCx<'mir, 'tcx>) -> CheckAlignment {
+        if ecx.machine.check_alignment == AlignmentCheck::None {
+            CheckAlignment::No
+        } else {
+            CheckAlignment::Error
+        }
     }
 
     #[inline(always)]
@@ -790,6 +795,15 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for MiriMachine<'mir, 'tcx> {
         ecx.machine.check_alignment == AlignmentCheck::Int
     }
 
+    fn alignment_check_failed(
+        _ecx: &InterpCx<'mir, 'tcx, Self>,
+        has: Align,
+        required: Align,
+        _check: CheckAlignment,
+    ) -> InterpResult<'tcx, ()> {
+        throw_ub!(AlignmentCheckFailed { has, required })
+    }
+
     #[inline(always)]
     fn enforce_validity(ecx: &MiriInterpCx<'mir, 'tcx>) -> bool {
         ecx.machine.validate