Remove getSubtargetImpl calls from FastISel, we can get it from
the MachineFunction where it's already cached.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219366 91177308-0d34-0410-b5e6-96231b3b80d8
Use both the cached TLI and the subtarget off of the DAG in
the DAG combiner.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219367 91177308-0d34-0410-b5e6-96231b3b80d8
Remove unnecessary include.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219368 91177308-0d34-0410-b5e6-96231b3b80d8