Sorry for the lack testcase. There is one in the pr, but it depends on
std::sort and the .ll version is 110 lines, so I don't think it is
wort it.
The bug was that we were sorting after adding a terminator, and the
sorting algorithm could end up putting the terminator in the middle of
the List vector.
With that we would create a Spans map entry keyed on nullptr which would
then be added to CUs and fail in that sorting.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270165 91177308-0d34-0410-b5e6-96231b3b80d8
e5257f1c4b