diff --git a/llvm/include/llvm/CodeGen/MachinePostDominators.h b/llvm/include/llvm/CodeGen/MachinePostDominators.h
index 904c5fcdfc68b..7769d4b426c7a 100644
--- a/llvm/include/llvm/CodeGen/MachinePostDominators.h
+++ b/llvm/include/llvm/CodeGen/MachinePostDominators.h
@@ -49,7 +49,7 @@ class MachinePostDominatorTree : public PostDomTreeBase<MachineBasicBlock> {
 public:
   MachinePostDominatorTree() = default;
 
-  MachinePostDominatorTree(MachineFunction &MF) { recalculate(MF); }
+  explicit MachinePostDominatorTree(MachineFunction &MF) { recalculate(MF); }
 
   /// Handle invalidation explicitly.
   bool invalidate(MachineFunction &, const PreservedAnalyses &PA,