vendor/llvm/llvm-trunk-r300422

1 files changed, 5 insertions, 2 deletions

diff --git a/include/llvm/Analysis/AliasSetTracker.h b/include/llvm/Analysis/AliasSetTracker.h
index 5d11b22c6eed9..eac97501c759c 100644
--- a/include/llvm/Analysis/AliasSetTracker.h
+++ b/include/llvm/Analysis/AliasSetTracker.h
@@ -121,7 +121,10 @@ class AliasSet : public ilist_node<AliasSet> {
   AliasSet *Forward;
 
   /// All instructions without a specific address in this alias set.
-  std::vector<AssertingVH<Instruction> > UnknownInsts;
+  /// In rare cases this vector can have a null'ed out WeakVH
+  /// instances (can happen if some other loop pass deletes an
+  /// instruction in this list).
+  std::vector<WeakVH> UnknownInsts;
 
   /// Number of nodes pointing to this AliasSet plus the number of AliasSets
   /// forwarding to it.
@@ -171,7 +174,7 @@ class AliasSet : public ilist_node<AliasSet> {
 
   Instruction *getUnknownInst(unsigned i) const {
     assert(i < UnknownInsts.size());
-    return UnknownInsts[i];
+    return cast_or_null<Instruction>(UnknownInsts[i]);
   }
 
 public: