diff --git a/src/libcore/lib.rs b/src/libcore/lib.rs
index 1efd605112dc2..448e49ffebda8 100644
--- a/src/libcore/lib.rs
+++ b/src/libcore/lib.rs
@@ -74,7 +74,9 @@
 #![feature(concat_idents)]
 #![feature(const_fn)]
 #![feature(custom_attribute)]
+#![feature(doc_cfg)]
 #![feature(doc_spotlight)]
+#![feature(fn_must_use)]
 #![feature(fundamental)]
 #![feature(i128_type)]
 #![feature(inclusive_range_syntax)]
diff --git a/src/stdsimd b/src/stdsimd
index 678cbd325c840..ab9356f2af650 160000
--- a/src/stdsimd
+++ b/src/stdsimd
@@ -1 +1 @@
-Subproject commit 678cbd325c84070c9dbe4303969fbd2734c0b4ee
+Subproject commit ab9356f2af650815d339d77306f0d09c44d531ad