minor cleanups


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@43881 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Rewrite/Rewriter.cpp b/Rewrite/Rewriter.cpp
index 5e6374e..1df169a 100644
--- a/Rewrite/Rewriter.cpp
+++ b/Rewrite/Rewriter.cpp
@@ -105,7 +105,7 @@
   unsigned RealOffset = getMappedOffset(OrigOffset, true);
   assert(RealOffset <= Buffer.size() && "Invalid location");
 
-  // Remove the dead characters.
+  // Insert the new characters.
   Buffer.insert(Buffer.begin()+RealOffset, StrData, StrData+StrLen);
   
   // Add a delta so that future changes are offset correctly.
@@ -121,8 +121,8 @@
   assert(RealOffset+OrigLength <= Buffer.size() && "Invalid location");
 
   // Overwrite the common piece.
-  std::copy(NewStr, NewStr+std::min(OrigLength, NewLength),
-            Buffer.begin()+RealOffset);
+  unsigned CommonLength = std::min(OrigLength, NewLength);
+  std::copy(NewStr, NewStr+CommonLength, Buffer.begin()+RealOffset);
   
   // If replacing without shifting around, just overwrite the text.
   if (OrigLength == NewLength)