Cleanup the AttributeSetNodes that we create.

llvm-svn: 173311
diff --git a/llvm/lib/IR/LLVMContextImpl.cpp b/llvm/lib/IR/LLVMContextImpl.cpp
index 8fc9379..89e163f 100644
--- a/llvm/lib/IR/LLVMContextImpl.cpp
+++ b/llvm/lib/IR/LLVMContextImpl.cpp
@@ -109,6 +109,13 @@
     delete &*Elem;
   }
 
+  // Destroy attribute node lists.
+  for (FoldingSetIterator<AttributeSetNode> I = AttrsSetNodes.begin(),
+         E = AttrsSetNodes.end(); I != E; ) {
+    FoldingSetIterator<AttributeSetNode> Elem = I++;
+    delete &*Elem;
+  }
+
   // Destroy MDNodes.  ~MDNode can move and remove nodes between the MDNodeSet
   // and the NonUniquedMDNodes sets, so copy the values out first.
   SmallVector<MDNode*, 8> MDNodes;