diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs
index be734a9ba5298..ab8d9f33b08b4 100644
--- a/library/core/src/lib.rs
+++ b/library/core/src/lib.rs
@@ -418,6 +418,7 @@ pub mod primitive;
 // FIXME: This annotation should be moved into rust-lang/stdarch after clashing_extern_declarations is
 // merged. It currently cannot because bootstrap fails as the lint hasn't been defined yet.
 #[allow(clashing_extern_declarations)]
+#[cfg_attr(bootstrap, allow(deprecated_in_future))]
 #[unstable(feature = "stdsimd", issue = "48556")]
 mod core_arch;
 
diff --git a/library/stdarch b/library/stdarch
index 6100854c4b360..333e9e9977188 160000
--- a/library/stdarch
+++ b/library/stdarch
@@ -1 +1 @@
-Subproject commit 6100854c4b360f84da5ab25e7c75cb2080667ddc
+Subproject commit 333e9e9977188d0748327e9b5be0f3f412063174