Fix typo to make grep for DW_AT_comp_dir work without case-insensitive
grep.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185496 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.h b/lib/CodeGen/AsmPrinter/DwarfDebug.h
index e28f708..00f50c5 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -387,7 +387,7 @@
   MCSymbol *DwarfAbbrevDWOSectionSym, *DwarfStrDWOSectionSym;
 
   // As an optimization, there is no need to emit an entry in the directory
-  // table for the same directory as DW_at_comp_dir.
+  // table for the same directory as DW_AT_comp_dir.
   StringRef CompilationDir;
 
   // Counter for assigning globally unique IDs for CUs.