diff --git a/polly/include/polly/Support/GICHelper.h b/polly/include/polly/Support/GICHelper.h
--- a/polly/include/polly/Support/GICHelper.h
+++ b/polly/include/polly/Support/GICHelper.h
@@ -152,9 +152,7 @@
 //@{
 #define ISL_CPP_OBJECT_TO_STRING(name)                                         \
   inline std::string stringFromIslObj(const name &Obj,                         \
-                                      std::string DefaultValue = "");          \
-  inline std::string stringFromIslObj(const name &Obj,                         \
-                                      std::string DefaultValue) {              \
+                                      std::string DefaultValue = "") {         \
     return stringFromIslObj(Obj.get(), DefaultValue);                          \
   }