Driver: Fix think in ArgList::MakeIndex.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@66908 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Driver/ArgList.cpp b/lib/Driver/ArgList.cpp
index 87847c0..184725f 100644
--- a/lib/Driver/ArgList.cpp
+++ b/lib/Driver/ArgList.cpp
@@ -54,7 +54,7 @@
 unsigned ArgList::MakeIndex(const char *String0, const char *String1) {
   unsigned Index0 = MakeIndex(String0);
   unsigned Index1 = MakeIndex(String1);
-  assert(Index0 == Index1 && "Unexpected non-consecutive indices!");
+  assert(Index0 + 1 == Index1 && "Unexpected non-consecutive indices!");
   (void) Index1;
   return Index0;
 }