11 // The safe point for the prologue (resp. epilogue) is called Save
15 // between 2) two executions of the Save (resp. Restore) point there is an
16 // execution of the Restore (resp. Save) point.
20 //   Save
24 // Indeed, the execution looks like Save -> Restore -> Save -> Restore ...
27 //   Save
34 // Indeed, the execution looks like Save -> Save -> ... -> Restore -> Restore.
123   MachineBasicBlock *Save = nullptr;  member in __anon8a4a73dd0111::ShrinkWrap
134   /// Hold the loop information. Used to determine if Save and Restore
173   /// after Save and before Restore.
192   /// Update the Save and Restore points such that \p MBB is in
193   /// the region that is dominated by Save and post-dominated by Restore
194   /// and Save and Restore still match the safe point definition.
195   /// Such point may not exist and Save and/or Restore may be null after
206   /// save point further. \return True if restore point is split.
212   /// 1. Any preds of current restore that are reachable by callee save/FI
230     Save = nullptr;  in init()
248   /// Check whether or not Save and Restore points are still interesting for
250   bool ArePointsInteresting() const { return Save != Entry && Save && Restore; }  in ArePointsInteresting()
588     InitSave = Save;  in postShrinkWrapping()
640   // Trying to reach out to the new save point which dominates all dirty blocks.  in postShrinkWrapping()
659   // from clean blocks and doing so can shrink the save point.  in postShrinkWrapping()
670   Save = NewSave;  in postShrinkWrapping()
676   assert((MDT->dominates(Save, Restore) && MPDT->dominates(Restore, Save)) &&  in postShrinkWrapping()
677          "Incorrect save or restore point due to dominance relations");  in postShrinkWrapping()
678   assert((!MLI->getLoopFor(Save) && !MLI->getLoopFor(Restore)) &&  in postShrinkWrapping()
679          "Unexpected save or restore point in a loop");  in postShrinkWrapping()
680   assert((EntryFreq >= MBFI->getBlockFreq(Save) &&  in postShrinkWrapping()
682          "Incorrect save or restore point based on block frequency");  in postShrinkWrapping()
689   if (!Save)  in updateSaveRestorePoints()
690     Save = &MBB;  in updateSaveRestorePoints()
692     Save = MDT->findNearestCommonDominator(Save, &MBB);  in updateSaveRestorePoints()
693   assert(Save);  in updateSaveRestorePoints()
730   // Make sure Save and Restore are suitable for shrink-wrapping:  in updateSaveRestorePoints()
731   // 1. all path from Save needs to lead to Restore before exiting.  in updateSaveRestorePoints()
732   // 2. all path to Restore needs to go through Save from Entry.  in updateSaveRestorePoints()
734   // A. Save dominates Restore.  in updateSaveRestorePoints()
735   // B. Restore post-dominates Save.  in updateSaveRestorePoints()
736   // C. Save and Restore are in the same loop.  in updateSaveRestorePoints()
740          (!(SaveDominatesRestore = MDT->dominates(Save, Restore)) ||  in updateSaveRestorePoints()
741           !(RestorePostDominatesSave = MPDT->dominates(Restore, Save)) ||  in updateSaveRestorePoints()
746           //  Save  in updateSaveRestorePoints()
752           // All the uses/defs of CSRs are dominated by Save and post-dominated  in updateSaveRestorePoints()
754           // Restore and before Save are executed.  in updateSaveRestorePoints()
756           // For now, just push the restore/save points outside of loops.  in updateSaveRestorePoints()
759           MLI->getLoopFor(Save) || MLI->getLoopFor(Restore))) {  in updateSaveRestorePoints()
762       Save = MDT->findNearestCommonDominator(Save, Restore);  in updateSaveRestorePoints()
767       Restore = MPDT->findNearestCommonDominator(Restore, Save);  in updateSaveRestorePoints()
770     if (Restore && (MLI->getLoopFor(Save) || MLI->getLoopFor(Restore))) {  in updateSaveRestorePoints()
771       if (MLI->getLoopDepth(Save) > MLI->getLoopDepth(Restore)) {  in updateSaveRestorePoints()
772         // Push Save outside of this loop if immediate dominator is different  in updateSaveRestorePoints()
773         // from save block. If immediate dominator is not different, bail out.  in updateSaveRestorePoints()
774         Save = FindIDom<>(*Save, Save->predecessors(), *MDT);  in updateSaveRestorePoints()
775         if (!Save)  in updateSaveRestorePoints()
831       // are at least at the boundary of the save and restore points.  The  in performShrinkWrapping()
857         // Save (resp. restore) point must dominate (resp. post dominate)  in performShrinkWrapping()
861         // save/restore instructions, just give up.  in performShrinkWrapping()
878     assert(!Save && !Restore && "We miss a shrink-wrap opportunity?!");  in performShrinkWrapping()
890                       << printMBBReference(*Save) << ' '  in performShrinkWrapping()
891                       << printBlockFreq(*MBFI, *Save)  in performShrinkWrapping()
896     if (((IsSaveCheap = EntryFreq >= MBFI->getBlockFreq(Save)) &&  in performShrinkWrapping()
898         ((TargetCanUseSaveAsPrologue = TFI->canUseAsPrologue(*Save)) &&  in performShrinkWrapping()
905       Save = FindIDom<>(*Save, Save->predecessors(), *MDT);  in performShrinkWrapping()
906       if (!Save)  in performShrinkWrapping()
908       NewBB = Save;  in performShrinkWrapping()
917   } while (Save && Restore);  in performShrinkWrapping()
966                     << printMBBReference(*Save) << ' '  in runOnMachineFunction()
970   MFI.setSavePoint(Save);  in runOnMachineFunction()