diff --git a/src/librustc_mir/interpret/operand.rs b/src/librustc_mir/interpret/operand.rs
index ba995afddc81..61c3c6f24ffb 100644
--- a/src/librustc_mir/interpret/operand.rs
+++ b/src/librustc_mir/interpret/operand.rs
@@ -295,7 +295,7 @@ pub(super) fn try_read_immediate_from_mplace(
                 let a_val = self.memory
                     .get(ptr.alloc_id)?
                     .read_scalar(self, a_ptr, a_size)?;
-                self.memory.check_align(b_ptr.into(), b.align(self))?;
+                self.memory.check_align(b_ptr.into(), b.align(self).min(ptr_align))?;
                 let b_val = self.memory
                     .get(ptr.alloc_id)?
                     .read_scalar(self, b_ptr, b_size)?;