diff --git a/llvm/include/llvm/CodeGen/ScheduleDFS.h b/llvm/include/llvm/CodeGen/ScheduleDFS.h
index d60deab95f5d..2e0a30cc56e3 100644
--- a/llvm/include/llvm/CodeGen/ScheduleDFS.h
+++ b/llvm/include/llvm/CodeGen/ScheduleDFS.h
@@ -13,7 +13,6 @@
 #ifndef LLVM_CODEGEN_SCHEDULEDFS_H
 #define LLVM_CODEGEN_SCHEDULEDFS_H
 
-#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/CodeGen/ScheduleDAG.h"
 #include <cassert>
@@ -22,6 +21,7 @@
 
 namespace llvm {
 
+template <typename T> class ArrayRef;
 class raw_ostream;
 
 /// Represent the ILP of the subDAG rooted at a DAG node.