comment grammar

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150233 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/Passes.cpp b/lib/CodeGen/Passes.cpp
index 5a7ec66..abf6778 100644
--- a/lib/CodeGen/Passes.cpp
+++ b/lib/CodeGen/Passes.cpp
@@ -205,7 +205,7 @@
 /// technique has maintainability tradeoffs because alternate pass orders are
 /// not well supported. addPre/Post works better if the target pass is easily
 /// tied to a common pass. But if it has subtle dependencies on multiple passes,
-/// overriding the stage instead.
+/// the target should override the stage instead.
 ///
 /// TODO: We could use a single addPre/Post(ID) hook to allow pass injection
 /// before/after any target-independent pass. But it's currently overkill.