does this help perf?

Author: RalfJung

compiler/rustc_const_eval/src/interpret/memory.rs

@@ -455,10 +455,6 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         ptr: Pointer<Option<M::Provenance>>,
         align: Align,
     ) -> Option<Misalignment> {
-        if !M::enforce_alignment(self) || align.bytes() == 1 {
-            return None;
-        }
-
         #[inline]
         fn offset_misalignment(offset: u64, align: Align) -> Option<Misalignment> {
             if offset % align.bytes() == 0 {
@@ -497,6 +493,9 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         ptr: Pointer<Option<M::Provenance>>,
         align: Align,
     ) -> InterpResult<'tcx> {
+        if !M::enforce_alignment(self) || align.bytes() == 1 {
+            return Ok(());
+        }
         self.check_misalign(self.is_ptr_misaligned(ptr, align), CheckAlignMsg::AccessedPtr)
     }
 }

compiler/rustc_const_eval/src/interpret/place.rs

@@ -381,7 +381,11 @@ where
         meta: MemPlaceMeta<M::Provenance>,
         layout: TyAndLayout<'tcx>,
     ) -> MPlaceTy<'tcx, M::Provenance> {
-        let misaligned = self.is_ptr_misaligned(ptr, layout.align.abi);
+        let misaligned = if !M::enforce_alignment(self) || layout.align.abi.bytes() == 1 {
+            None
+        } else {
+            self.is_ptr_misaligned(ptr, layout.align.abi)
+        };
         MPlaceTy { mplace: MemPlace { ptr, meta, misaligned }, layout }
     }