diff --git a/bolt/lib/Passes/CallGraph.cpp b/bolt/lib/Passes/CallGraph.cpp
index 3d4157509700..7fa6562a8c12 100644
--- a/bolt/lib/Passes/CallGraph.cpp
+++ b/bolt/lib/Passes/CallGraph.cpp
@@ -24,7 +24,7 @@
 
 namespace {
 
-inline size_t hash_int64_fallback(int64_t k) {
+LLVM_ATTRIBUTE_UNUSED inline size_t hash_int64_fallback(int64_t k) {
   uint64_t key = (unsigned long long)k;
   // "64 bit Mix Functions", from Thomas Wang's "Integer Hash Function."
   // http://www.concentric.net/~ttwang/tech/inthash.htm
@@ -37,7 +37,7 @@ inline size_t hash_int64_fallback(int64_t k) {
   return static_cast<size_t>(static_cast<uint32_t>(key));
 }
 
-inline size_t hash_int64(int64_t k) {
+LLVM_ATTRIBUTE_UNUSED inline size_t hash_int64(int64_t k) {
 #if defined(USE_SSECRC) && defined(__SSE4_2__)
   size_t h = 0;
   __asm("crc32q %1, %0\n" : "+r"(h) : "rm"(k));