diff --git a/compiler/rustc_data_structures/src/fingerprint.rs b/compiler/rustc_data_structures/src/fingerprint.rs
index 1c929afb1cf36..6fa76981408ca 100644
--- a/compiler/rustc_data_structures/src/fingerprint.rs
+++ b/compiler/rustc_data_structures/src/fingerprint.rs
@@ -14,12 +14,14 @@ pub trait FingerprintComponent {
 }
 
 impl FingerprintComponent for Hash64 {
+    #[inline]
     fn as_u64(&self) -> u64 {
         Hash64::as_u64(*self)
     }
 }
 
 impl FingerprintComponent for u64 {
+    #[inline]
     fn as_u64(&self) -> u64 {
         *self
     }
diff --git a/compiler/rustc_data_structures/src/hashes.rs b/compiler/rustc_data_structures/src/hashes.rs
index f32f691226760..ad068cdbc9841 100644
--- a/compiler/rustc_data_structures/src/hashes.rs
+++ b/compiler/rustc_data_structures/src/hashes.rs
@@ -36,6 +36,7 @@ impl Hash64 {
 }
 
 impl BitXorAssign<u64> for Hash64 {
+    #[inline]
     fn bitxor_assign(&mut self, rhs: u64) {
         self.inner ^= rhs;
     }
diff --git a/compiler/rustc_span/src/def_id.rs b/compiler/rustc_span/src/def_id.rs
index f05328ac1b423..6004009c6ff1b 100644
--- a/compiler/rustc_span/src/def_id.rs
+++ b/compiler/rustc_span/src/def_id.rs
@@ -186,6 +186,7 @@ impl StableCrateId {
         StableCrateId(hasher.finish())
     }
 
+    #[inline]
     pub fn as_u64(self) -> u64 {
         self.0.as_u64()
     }