[MachinePipeliner] Remove unused LoopInfo data fields

[ivafanas]

Summary

LoopInductionVar and LoopCompare data members of MachinePipeliner::LoopInfo struct seems to be unused asf ar as nobody reads their value. Should be removed.

[ivafanas]

Ping, please

[kparzysz]

LGTM!

llvm/include/llvm/CodeGen/MachinePipeliner.h

#ifndef NDEBUG
   static int NumTries;
 #endif
 
   /// Cache the target analysis information about the loop.
   struct LoopInfo {
     MachineBasicBlock *TBB = nullptr;
     MachineBasicBlock *FBB = nullptr;
     SmallVector<MachineOperand, 4> BrCond;
-    MachineInstr *LoopInductionVar = nullptr;
-    MachineInstr *LoopCompare = nullptr;
     std::unique_ptr<TargetInstrInfo::PipelinerLoopInfo> LoopPipelinerInfo =
         nullptr;
   };
   LoopInfo LI;
 
   static char ID;
 
   MachinePipeliner() : MachineFunctionPass(ID) {

llvm/lib/CodeGen/MachinePipeliner.cpp

if (TII->analyzeBranch(*L.getHeader(), LI.TBB, LI.FBB, LI.BrCond)) {
     ORE->emit([&]() {
       return MachineOptimizationRemarkAnalysis(DEBUG_TYPE, "canPipelineLoop",
                                                L.getStartLoc(), L.getHeader())
              << "The branch can't be understood";
     });
     return false;
   }
 
-  LI.LoopInductionVar = nullptr;
-  LI.LoopCompare = nullptr;
   LI.LoopPipelinerInfo = TII->analyzeLoopForPipelining(L.getTopBlock());
   if (!LI.LoopPipelinerInfo) {
     LLVM_DEBUG(dbgs() << "Unable to analyzeLoop, can NOT pipeline Loop\n");
     NumFailLoop++;
     ORE->emit([&]() {
       return MachineOptimizationRemarkAnalysis(DEBUG_TYPE, "canPipelineLoop",
                                                L.getStartLoc(), L.getHeader())
              << "The loop structure is not supported";