diff --git a/src/librustc_data_structures/bitslice.rs b/src/librustc_data_structures/bitslice.rs
index 7665bfd5b1117..2678861be0634 100644
--- a/src/librustc_data_structures/bitslice.rs
+++ b/src/librustc_data_structures/bitslice.rs
@@ -24,6 +24,7 @@ pub trait BitSlice {
 
 impl BitSlice for [Word] {
     /// Clears bit at `idx` to 0; returns true iff this changed `self.`
+    #[inline]
     fn clear_bit(&mut self, idx: usize) -> bool {
         let words = self;
         debug!("clear_bit: words={} idx={}",
@@ -37,6 +38,7 @@ impl BitSlice for [Word] {
     }
 
     /// Sets bit at `idx` to 1; returns true iff this changed `self.`
+    #[inline]
     fn set_bit(&mut self, idx: usize) -> bool {
         let words = self;
         debug!("set_bit: words={} idx={}",
@@ -50,6 +52,7 @@ impl BitSlice for [Word] {
     }
 
     /// Extracts value of bit at `idx` in `self`.
+    #[inline]
     fn get_bit(&self, idx: usize) -> bool {
         let words = self;
         let BitLookup { word, bit_mask, .. } = bit_lookup(idx);
diff --git a/src/librustc_data_structures/indexed_vec.rs b/src/librustc_data_structures/indexed_vec.rs
index 3e94b3f4d302a..11c2bd7368760 100644
--- a/src/librustc_data_structures/indexed_vec.rs
+++ b/src/librustc_data_structures/indexed_vec.rs
@@ -29,12 +29,16 @@ pub trait Idx: Copy + 'static + Eq + Debug {
 }
 
 impl Idx for usize {
+    #[inline]
     fn new(idx: usize) -> Self { idx }
+    #[inline]
     fn index(self) -> usize { self }
 }
 
 impl Idx for u32 {
+    #[inline]
     fn new(idx: usize) -> Self { assert!(idx <= u32::MAX as usize); idx as u32 }
+    #[inline]
     fn index(self) -> usize { self as usize }
 }
 
@@ -73,11 +77,13 @@ macro_rules! newtype_index {
         pub struct $type($($pub)* u32);
 
         impl Idx for $type {
+            #[inline]
             fn new(value: usize) -> Self {
                 assert!(value < ($max) as usize);
                 $type(value as u32)
             }
 
+            #[inline]
             fn index(self) -> usize {
                 self.0 as usize
             }