Fix subtle bug in Preprocessor::AdvanceToTokenCharacter(): use '+=' instead of '='.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@94830 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Lex/Preprocessor.cpp b/lib/Lex/Preprocessor.cpp
index 5689baa..df0e702 100644
--- a/lib/Lex/Preprocessor.cpp
+++ b/lib/Lex/Preprocessor.cpp
@@ -424,7 +424,7 @@
   // advanced by 3 should return the location of b, not of \\.  One compounding
   // detail of this is that the escape may be made by a trigraph.
   if (!Lexer::isObviouslySimpleCharacter(*TokPtr))
-    PhysOffset = Lexer::SkipEscapedNewLines(TokPtr)-TokPtr;
+    PhysOffset += Lexer::SkipEscapedNewLines(TokPtr)-TokPtr;
 
   return TokStart.getFileLocWithOffset(PhysOffset);
 }