the SelectionDAG and DAGCombiner code. The only functionality change is that now
the DAG combiner is performing the constant folding for these operations instead
of being a no-op.
This is *not* in response to a bug, so there isn't a testcase.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56550 91177308-0d34-0410-b5e6-96231b3b80d8