AsmPrinter.cpp

      O.PadToColumn(MAI->getCommentColumn());

      MachineBasicBlock *Header = loop->getHeader();
      assert(Header && "No header for loop");
      
      if (Header == &MBB) {
        O << MAI->getCommentString() << " Loop Header";
        PrintChildLoopComment(O, loop, MAI, getFunctionNumber());
      }
      else {
        O << MAI->getCommentString() << " Loop Header is BB"
          << getFunctionNumber() << "_" << loop->getHeader()->getNumber();
      }

      if (loop->empty()) {
        O << '\n';
        O.PadToColumn(MAI->getCommentColumn());
        O << MAI->getCommentString() << " Inner Loop";
      }

      // Add parent loop information
      for (const MachineLoop *CurLoop = loop->getParentLoop();
           CurLoop;
           CurLoop = CurLoop->getParentLoop()) {
        MachineBasicBlock *Header = CurLoop->getHeader();
        assert(Header && "No header for loop");

        O << '\n';
        O.PadToColumn(MAI->getCommentColumn());
        O << MAI->getCommentString();
        O.indent((CurLoop->getLoopDepth()-1)*2)
          << " Inside Loop BB" << getFunctionNumber() << "_"
          << Header->getNumber() << " Depth " << CurLoop->getLoopDepth();
      }
    }
  }
}