Target/ARM/ARMLowOverheadLoops.cpp

127     MachineInstr *Start = nullptr;
163     // value, or if it's going to be equivalent to the operand to Start.
172       return Start && Dec && End;
181         VCTP->getOperand(1) : Start->getOperand(0);
185       bool IsDo = Start->getOpcode() == ARM::t2DoLoopStart;
193       if (Start) dbgs() << "ARM Loops: Found Loop Start: " << *Start;
199       else if (!(Start && Dec && End))
266   if (Start->getOperand(0).getReg() == ARM::LR)
267     return Start;
269   unsigned CountReg = Start->getOperand(0).getReg();
277   MachineBasicBlock *MBB = Start->getParent();
280   // - Is there a (mov lr, Count) before Start? If so, and nothing else writes
281   //   to Count before Start, we can insert at that mov.
282   if (auto *LRDef = RDA->getReachingMIDef(Start, ARM::LR))
283     if (IsMoveLR(LRDef) && RDA->hasSameReachingDef(Start, LRDef, CountReg))
286   // - Is there a (mov lr, Count) after Start? If so, and nothing else writes
287   //   to Count after Start, we can insert at that mov.
289     if (IsMoveLR(LRDef) && RDA->hasSameReachingDef(Start, LRDef, CountReg))
292   // We've found no suitable LR def and Start doesn't use LR directly. Can we
294   if (!RDA->isRegUsedAfter(Start, ARM::LR))
295     return Start;
452   if (Start->getOpcode() == ARM::t2WhileLoopStart &&
453       (BBUtils->getOffsetOf(Start) >
454        BBUtils->getOffsetOf(Start->getOperand(1).getMBB()) ||
455        !BBUtils->isBBInRange(Start, Start->getOperand(1).getMBB(), 4094))) {
467     LLVM_DEBUG(dbgs() << "ARM Loops: Start insertion point: " << *InsertPt);
491   // Start a new vpt block when we discover a vpt.
616     LoLoop.Start = SearchForStart(Preheader);
618     LoLoop.Start = SearchForStart(Preheader);
632         LoLoop.Start = &MI;
764   MachineInstr *Start = LoLoop.Start;
766   bool IsDo = Start->getOpcode() == ARM::t2DoLoopStart;
776     MIB.add(Start->getOperand(1));
783     if (auto *Def = RDA->getReachingMIDef(Start,
784                                           Start->getOperand(0).getReg())) {
806   if (InsertPt != Start)
808   Start->eraseFromParent();
1000     if (LoLoop.Start->getOpcode() == ARM::t2WhileLoopStart)
1001       RevertWhile(LoLoop.Start);
1003       LoLoop.Start->eraseFromParent();
1007     LoLoop.Start = ExpandLoopStart(LoLoop);
1008     RemoveDeadBranch(LoLoop.Start);
1041     for (auto *Start : Starts) {
1042       if (Start->getOpcode() == ARM::t2WhileLoopStart)
1043         RevertWhile(Start);
1045         Start->eraseFromParent();