in any old order. Since analyzing a node analyzes its
operands also, this can mean that when we pop a node
off the list of nodes to be analyzed, it may already
have been analyzed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63632 91177308-0d34-0410-b5e6-96231b3b80d8
