diff --git a/include/llvm/ADT/APFloat.h b/include/llvm/ADT/APFloat.h
index baa9de02578..b53f9fb3770 100644
--- a/include/llvm/ADT/APFloat.h
+++ b/include/llvm/ADT/APFloat.h
@@ -168,9 +168,9 @@ namespace llvm {
     APFloat(const fltSemantics &, const char *);
     APFloat(const fltSemantics &, integerPart);
     APFloat(const fltSemantics &, fltCategory, bool negative);
-    APFloat(double d);
-    APFloat(float f);
-    APFloat(const APInt &);
+    explicit APFloat(double d);
+    explicit APFloat(float f);
+    explicit APFloat(const APInt &);
     APFloat(const APFloat &);
     ~APFloat();