diff --git a/include/clang/AST/Expr.h b/include/clang/AST/Expr.h
index 51b8588d5f..692a0ea85f 100644
--- a/include/clang/AST/Expr.h
+++ b/include/clang/AST/Expr.h
@@ -481,6 +481,10 @@ public:
   /// isPostfix - Return true if this is a postfix operation, like x++.
   static bool isPostfix(Opcode Op);
 
+  /// isPostfix - Return true if this is a prefix operation, like --x.
+  static bool isPrefix(Opcode Op);
+
+  bool isPrefix() const { return isPrefix(Opc); }
   bool isPostfix() const { return isPostfix(Opc); }
   bool isIncrementOp() const {return Opc==PreInc || Opc==PostInc; }
   bool isIncrementDecrementOp() const { return Opc>=PostInc && Opc<=PreDec; }
diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index de0c740fd2..6c7d170d03 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -61,6 +61,16 @@ bool UnaryOperator::isPostfix(Opcode Op) {
   }
 }
 
+bool UnaryOperator::isPrefix(Opcode Op) {
+  switch (Op) {
+    case PreInc:
+    case PreDec:
+      return true;
+    default:
+      return false;
+  }
+}
+
 /// getOpcodeStr - Turn an Opcode enum value into the punctuation char it
 /// corresponds to, e.g. "sizeof" or "[pre]++".
 const char *UnaryOperator::getOpcodeStr(Opcode Op) {