a) Move the replacement level decision to the target machine.
b) Create additional subtargets at the TargetMachine level to
cache and make replacement easy.
c) Make the mips16 features obvious.
d) Remove the override logic as it no longer does anything.
e) Have MipsModuleDAGToDAGISel take only the target machine.
f) Have the constant islands pass grab the current subtarget
from the MachineFunction (via the TargetMachine) instead
of caching it.
g) Unconditionally initialize TLOF.
h) Remove the old complicated subtarget based resetting and
replace it with simple conditionals.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213430 91177308-0d34-0410-b5e6-96231b3b80d8
ec3b0fef11