diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 554aa1c..87e7454 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -1995,7 +1995,7 @@
   IsUTF16 = true;
 
   SmallVector<UTF16, 128> ToBuf(NumBytes + 1); // +1 for ending nulls.
-  const UTF8 *FromPtr = (UTF8 *)String.data();
+  const UTF8 *FromPtr = (const UTF8 *)String.data();
   UTF16 *ToPtr = &ToBuf[0];
 
   (void)ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes,