Explain change with a comment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30443 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Analysis/AliasSetTracker.cpp b/lib/Analysis/AliasSetTracker.cpp
index 39f01b613eced39093505da56e032a74d07feb9c..852def0b76736b0585ad1942df4ad021aa3178c1 100644 (file)
--- a/lib/Analysis/AliasSetTracker.cpp
+++ b/lib/Analysis/AliasSetTracker.cpp
@@ -374,8 +374,8 @@ void AliasSetTracker::remove(AliasSet &AS) {
     ++NumRefs;
 
     // Finally, remove the entry.
-    Value *Remove = P->first;
-    PointerMap.erase(Remove);
+    Value *Remove = P->first;   // Take a copy because it is invalid to pass
+    PointerMap.erase(Remove);   // a reference to the data being erased.
   }
   
   // Stop using the alias set, removing it.