text: #!/usr/bin/env python
  
  from __future__ import print_function
  
  import os
  import sys
  import argparse
  import subprocess
  
  parser = argparse.ArgumentParser()
  
  parser.add_argument('--start', type=int, default=0)
  parser.add_argument('--end', type=int, default=(1 << 32))
  parser.add_argument('--optcmd', default=("opt"))
  parser.add_argument('--filecheckcmd', default=("FileCheck"))
  parser.add_argument('--prefix', default=("CHECK-BISECT"))
  parser.add_argument('--test', default=(""))
  
  args = parser.parse_args()
  
  start = args.start
  end = args.end
  
  opt_command = [args.optcmd, "-O2", "-opt-bisect-limit=%(count)s", "-S", args.test]
  check_command = [args.filecheckcmd, args.test, "--check-prefix=%s" % args.prefix]
  last = None
  while start != end and start != end-1:
      count = int(round(start + (end - start)/2))
      cmd = [x % {'count':count} for x in opt_command]
      print("opt: " + str(cmd))
      opt_result = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
      filecheck_result = subprocess.Popen(check_command, stdin=opt_result.stdout)
      opt_result.stdout.close()
      opt_result.stderr.close()
      filecheck_result.wait()
      if filecheck_result.returncode == 0:
          start = count
      else:
          end = count
  
  print("Last good count: %d" % start)
  