Fix VC++ compilation error.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@25577 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAGSimple.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAGSimple.cpp
index 71bf3cc..e088f71 100644
--- a/lib/CodeGen/SelectionDAG/ScheduleDAGSimple.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAGSimple.cpp
@@ -19,6 +19,7 @@
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetInstrInfo.h"
 #include "llvm/Support/Debug.h"
+#include <algorithm>
 using namespace llvm;
 
 namespace {