use drop_back

Author: arsenm

llvm/include/llvm/IR/RuntimeLibcalls.h

@@ -81,7 +81,10 @@ struct RuntimeLibcallsInfo {
     return LibcallCallingConvs[Call];
   }
 
-  ArrayRef<const char *> getLibcallNames() const { return LibcallRoutineNames; }
+  ArrayRef<const char *> getLibcallNames() const {
+    // Trim UNKNOWN_LIBCALL from the end
+    return ArrayRef(LibcallRoutineNames).drop_back();
+  }
 
 private:
   /// Stores the name each libcall.