diff --git a/lib/Lex/Preprocessor.cpp b/lib/Lex/Preprocessor.cpp
index 3175d04..d33d9c5 100644
--- a/lib/Lex/Preprocessor.cpp
+++ b/lib/Lex/Preprocessor.cpp
@@ -312,7 +312,7 @@
     MemoryBuffer *NewBuffer =
         MemoryBuffer::getNewUninitMemBuffer(Buffer->getBufferSize() + 1,
                                             Buffer->getBufferIdentifier());
-    char *NewBuf = (char*)NewBuffer->getBufferStart();
+    char *NewBuf = const_cast<char*>(NewBuffer->getBufferStart());
     char *NewPos = std::copy(Buffer->getBufferStart(), Position, NewBuf);
     *NewPos = '\0';
     std::copy(Position, Buffer->getBufferEnd(), NewPos+1);