[DAG] fix type of undef returned by getNode()

The bug has been lying dormant, but apparently was never exposed, until
after rL324941 because we didn't return the correct result 
for shifts with undef operands.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@325010 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed