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.)

llvm-svn: 304342

1 files changed, 5 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/MachineBasicBlock.cpp b/llvm/lib/CodeGen/MachineBasicBlock.cpp
index 0611272..2a2b43b 100644
--- a/llvm/lib/CodeGen/MachineBasicBlock.cpp
+++ b/llvm/lib/CodeGen/MachineBasicBlock.cpp
@@ -350,6 +350,11 @@ void MachineBasicBlock::removeLiveIn(MCPhysReg Reg, LaneBitmask LaneMask) {
     LiveIns.erase(I);
 }
 
+MachineBasicBlock::livein_iterator
+MachineBasicBlock::removeLiveIn(MachineBasicBlock::livein_iterator I) {
+  return LiveIns.erase(I);
+}
+
 bool MachineBasicBlock::isLiveIn(MCPhysReg Reg, LaneBitmask LaneMask) const {
   livein_iterator I = find_if(
       LiveIns, [Reg](const RegisterMaskPair &LI) { return LI.PhysReg == Reg; });