diff --git a/llvm/unittests/IR/CFGBuilder.cpp b/llvm/unittests/IR/CFGBuilder.cpp
index a0b9b0e6cf4a..50494ab5c7ca 100644
--- a/llvm/unittests/IR/CFGBuilder.cpp
+++ b/llvm/unittests/IR/CFGBuilder.cpp
@@ -16,8 +16,6 @@
 #include "llvm/Support/raw_ostream.h"
 #include "gtest/gtest.h"
 
-#include <tuple>
-
 #define DEBUG_TYPE "cfg-builder"
 
 using namespace llvm;
@@ -30,10 +28,6 @@ CFGHolder::CFGHolder(StringRef ModuleName, StringRef FunctionName)
 }
 CFGHolder::~CFGHolder() = default;
 
-bool llvm::operator<(const CFGBuilder::Arc &LHS, const CFGBuilder::Arc &RHS) {
-  return std::tie(LHS.From, LHS.To) < std::tie(RHS.From, RHS.To);
-}
-
 CFGBuilder::CFGBuilder(Function *F, const std::vector<Arc> &InitialArcs,
                        std::vector<Update> Updates)
     : F(F), Updates(std::move(Updates)) {
diff --git a/llvm/unittests/IR/CFGBuilder.h b/llvm/unittests/IR/CFGBuilder.h
index b6a27326f53c..d9d9c378e110 100644
--- a/llvm/unittests/IR/CFGBuilder.h
+++ b/llvm/unittests/IR/CFGBuilder.h
@@ -23,6 +23,7 @@
 
 #include <memory>
 #include <set>
+#include <tuple>
 #include <vector>
 
 namespace llvm {
@@ -56,7 +57,10 @@ public:
     StringRef From;
     StringRef To;
 
-    friend bool operator<(const Arc &LHS, const Arc &RHS);
+    friend bool operator<(const Arc &LHS, const Arc &RHS) {
+      return std::tie(LHS.From, LHS.To) <
+             std::tie(RHS.From, RHS.To);
+    }
   };
 
   enum class ActionKind { Insert, Delete };