add accessor, improve comment.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90792 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/PHITransAddr.cpp b/lib/Analysis/PHITransAddr.cpp
index 40800b4..9935b92 100644
--- a/lib/Analysis/PHITransAddr.cpp
+++ b/lib/Analysis/PHITransAddr.cpp
@@ -195,7 +195,7 @@
 
 /// PHITranslateValue - PHI translate the current address up the CFG from
 /// CurBB to Pred, updating our state the reflect any needed changes.  This
-/// returns true on failure.
+/// returns true on failure and sets Addr to null.
 bool PHITransAddr::PHITranslateValue(BasicBlock *CurBB, BasicBlock *PredBB) {
   Addr = PHITranslateSubExpr(Addr, CurBB, PredBB);
   return Addr == 0;