[Bug libstdc++/110287] _M_check_len is expensive

[hubicka at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110287

--- Comment #1 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
Another problem is:

  D.27747 = _8;
  if (__n.3_2 > _8)
    goto <bb 5>; [34.00%]
  else
    goto <bb 6>; [66.00%]

  <bb 5> [local count: 364926196]:

  <bb 6> [local count: 1073312330]:
  # _18 = PHI <&D.27747(4), &__n(5)>
  _3 = *_18;

which is simply computation of maximum but done in a way not understood until
phiprop