Add explicit keywords.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53179 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/Sparc/SparcISelDAGToDAG.cpp b/lib/Target/Sparc/SparcISelDAGToDAG.cpp
index 50690ca..df07d51 100644
--- a/lib/Target/Sparc/SparcISelDAGToDAG.cpp
+++ b/lib/Target/Sparc/SparcISelDAGToDAG.cpp
@@ -35,7 +35,7 @@
   /// make the right decision when generating code for different targets.
   const SparcSubtarget &Subtarget;
 public:
-  SparcDAGToDAGISel(TargetMachine &TM)
+  explicit SparcDAGToDAGISel(TargetMachine &TM)
     : SelectionDAGISel(Lowering), Lowering(TM),
       Subtarget(TM.getSubtarget<SparcSubtarget>()) {
   }