Fix VC++ compilation error.

llvm-svn: 25577
diff --git a/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSimple.cpp b/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSimple.cpp
index 71bf3cc..e088f71 100644
--- a/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSimple.cpp
+++ b/llvm/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 {