13 // (resp. Restore).
16 // between 2) two executions of the Save (resp. Restore) point there is an
17 // execution of the Restore (resp. Save) point.
23 //   Restore
25 // Indeed, the execution looks like Save -> Restore -> Save -> Restore ...
33 //   Restore
35 // Indeed, the execution looks like Save -> Save -> ... -> Restore -> Restore.
62 // For property #1 for Restore.
111   MachineBasicBlock *Restore;  member in __anon084c4c750111::ShrinkWrap
115   /// Hold the loop information. Used to determine if Save and Restore
134   /// after Save and before Restore.
152   /// \brief Update the Save and Restore points such that \p MBB is in
153   /// the region that is dominated by Save and post-dominated by Restore
154   /// and Save and Restore still match the safe point definition.
155   /// Such point may not exist and Save and/or Restore may be null after
165     Restore = nullptr;  in init()
179   /// Check whether or not Save and Restore points are still interesting for
181   bool ArePointsInteresting() const { return Save != Entry && Save && Restore; }  in ArePointsInteresting()
285   if (!Restore)  in updateSaveRestorePoints()
286     Restore = &MBB;  in updateSaveRestorePoints()
288     Restore = MPDT->findNearestCommonDominator(Restore, &MBB);  in updateSaveRestorePoints()
290   // Make sure we would be able to insert the restore code before the  in updateSaveRestorePoints()
292   if (Restore == &MBB) {  in updateSaveRestorePoints()
296       // One of the terminator needs to happen before the restore point.  in updateSaveRestorePoints()
298         Restore = nullptr;  in updateSaveRestorePoints()
301       // Look for a restore point that post-dominates all the successors.  in updateSaveRestorePoints()
303       Restore = FindIDom<>(*Restore, Restore->successors(), *MPDT);  in updateSaveRestorePoints()
308   if (!Restore) {  in updateSaveRestorePoints()
309     DEBUG(dbgs() << "Restore point needs to be spanned on several blocks\n");  in updateSaveRestorePoints()
313   // Make sure Save and Restore are suitable for shrink-wrapping:  in updateSaveRestorePoints()
314   // 1. all path from Save needs to lead to Restore before exiting.  in updateSaveRestorePoints()
315   // 2. all path to Restore needs to go through Save from Entry.  in updateSaveRestorePoints()
317   // A. Save dominates Restore.  in updateSaveRestorePoints()
318   // B. Restore post-dominates Save.  in updateSaveRestorePoints()
319   // C. Save and Restore are in the same loop.  in updateSaveRestorePoints()
322   while (Save && Restore &&  in updateSaveRestorePoints()
323          (!(SaveDominatesRestore = MDT->dominates(Save, Restore)) ||  in updateSaveRestorePoints()
324           !(RestorePostDominatesSave = MPDT->dominates(Restore, Save)) ||  in updateSaveRestorePoints()
330           //  Restore  in updateSaveRestorePoints()
336           // by Restore. However, the CSRs uses are still reachable after  in updateSaveRestorePoints()
337           // Restore and before Save are executed.  in updateSaveRestorePoints()
339           // For now, just push the restore/save points outside of loops.  in updateSaveRestorePoints()
342           MLI->getLoopFor(Save) || MLI->getLoopFor(Restore))) {  in updateSaveRestorePoints()
345       Save = MDT->findNearestCommonDominator(Save, Restore);  in updateSaveRestorePoints()
350       Restore = MPDT->findNearestCommonDominator(Restore, Save);  in updateSaveRestorePoints()
353     if (Save && Restore &&  in updateSaveRestorePoints()
354         (MLI->getLoopFor(Save) || MLI->getLoopFor(Restore))) {  in updateSaveRestorePoints()
355       if (MLI->getLoopDepth(Save) > MLI->getLoopDepth(Restore)) {  in updateSaveRestorePoints()
365         MLI->getLoopFor(Restore)->getExitingBlocks(ExitBlocks);  in updateSaveRestorePoints()
366         // Push Restore outside of this loop.  in updateSaveRestorePoints()
368         MachineBasicBlock *IPdom = Restore;  in updateSaveRestorePoints()
377         if (IPdom && MLI->getLoopDepth(IPdom) < MLI->getLoopDepth(Restore))  in updateSaveRestorePoints()
378           Restore = IPdom;  in updateSaveRestorePoints()
380           Restore = nullptr;  in updateSaveRestorePoints()
458       // Save (resp. restore) point must dominate (resp. post dominate)  in runOnMachineFunction()
462       // save/restore instructions, just give up.  in runOnMachineFunction()
476     assert(!Save && !Restore && "We miss a shrink-wrap opportunity?!");  in runOnMachineFunction()
489                  << Restore->getNumber() << ' ' << Restore->getName() << ' '  in runOnMachineFunction()
490                  << MBFI->getBlockFreq(Restore).getFrequency() << '\n');  in runOnMachineFunction()
494          EntryFreq >= MBFI->getBlockFreq(Restore).getFrequency()) &&  in runOnMachineFunction()
496          TFI->canUseAsEpilogue(*Restore)))  in runOnMachineFunction()
506       // Restore is expensive.  in runOnMachineFunction()
507       Restore = FindIDom<>(*Restore, Restore->successors(), *MPDT);  in runOnMachineFunction()
508       if (!Restore)  in runOnMachineFunction()
510       NewBB = Restore;  in runOnMachineFunction()
513   } while (Save && Restore);  in runOnMachineFunction()
522                << Restore->getNumber() << ' ' << Restore->getName() << '\n');  in runOnMachineFunction()
526   MFI->setRestorePoint(Restore);  in runOnMachineFunction()