add comments.

llvm-svn: 106616
diff --git a/clang/lib/Checker/OSAtomicChecker.cpp b/clang/lib/Checker/OSAtomicChecker.cpp
index e743528..44dcdd4 100644
--- a/clang/lib/Checker/OSAtomicChecker.cpp
+++ b/clang/lib/Checker/OSAtomicChecker.cpp
@@ -100,7 +100,9 @@
   const GRState *state = C.getState();
   ExplodedNodeSet Tmp;
   SVal location = state->getSVal(theValueExpr);
-  // Here we should use the value type of the region as the load type.
+  // Here we should use the value type of the region as the load type, because
+  // we are simulating the semantics of the function, not the semantics of 
+  // passing argument.
   QualType LoadTy;
   if (const TypedRegion *TR =
       dyn_cast_or_null<TypedRegion>(location.getAsRegion())) {