X86FloatingPoint: Fix livein lists

After transforming FP to ST registers:
- Do not add the ST register to the livein lists, they are reserved so
  we do not need to track their liveness.
- Remove the FP registers from the livein lists, they don't have defs or
  uses anymore and so are not live.
- (The setKillFlags() call is moved to an earlier place as it relies on
   the FP registers still being present in the livein list.)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304342 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed