Revert r153516: "Invalidate liveness in Thumb2ITBlockPass."

Revert r153519: "ARMLoadStoreOptimizer invalidates register liveness."

These patches caused miscompilations in povray by turning off branch
folding's updating of live-in lists.

It turns out the the late scheduler depends on the live-in lists, even
if it doesn't need correct kill flags.

<rdar://problem/11139228>

llvm-svn: 153593

llvm/lib/Target/ARM/ARMLoadStoreOptimizer.cpp

@@ -1411,10 +1411,6 @@ bool ARMLoadStoreOpt::runOnMachineFunction(MachineFunction &Fn) {
   }
 
   delete RS;
-
-  // Kill flags aren't updated accurately by this pass.
-  Fn.getRegInfo().invalidateLiveness();
-
   return Modified;
 }
 

llvm/lib/Target/ARM/Thumb2ITBlockPass.cpp

@@ -15,7 +15,6 @@
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineInstrBundle.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
-#include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/Statistic.h"
 using namespace llvm;
@@ -259,9 +258,6 @@ bool Thumb2ITBlockPass::runOnMachineFunction(MachineFunction &Fn) {
   if (!AFI->isThumbFunction())
     return false;
 
-  // IT block insertion invalidates accurate register liveness.
-  Fn.getRegInfo().invalidateLiveness();
-
   bool Modified = false;
   for (MachineFunction::iterator MFI = Fn.begin(), E = Fn.end(); MFI != E; ) {
     MachineBasicBlock &MBB = *MFI;