diff --git a/src/libstd/ffi/os_str.rs b/src/libstd/ffi/os_str.rs
index 4c308327b83..ec2d07f34ca 100644
--- a/src/libstd/ffi/os_str.rs
+++ b/src/libstd/ffi/os_str.rs
@@ -615,6 +615,7 @@ impl OsStr {
     /// assert!(!os_str.is_empty());
     /// ```
     #[stable(feature = "osstring_simple_functions", since = "1.9.0")]
+    #[inline]
     pub fn is_empty(&self) -> bool {
         self.inner.inner.is_empty()
     }
diff --git a/src/libstd/sys_common/os_str_bytes.rs b/src/libstd/sys_common/os_str_bytes.rs
index eb8a881ec88..e965ea79aa0 100644
--- a/src/libstd/sys_common/os_str_bytes.rs
+++ b/src/libstd/sys_common/os_str_bytes.rs
@@ -104,6 +104,7 @@ impl Buf {
         self.inner.shrink_to(min_capacity)
     }
 
+    #[inline]
     pub fn as_slice(&self) -> &Slice {
         unsafe { mem::transmute(&*self.inner) }
     }