[Bug target/100623] [10/11/12 Regression] wrong code with -Os -fno-dce -fno-defer-pop -fno-forward-propagate -flive-range-shrinkage -fno-rerun-cse-after-loop -mno-push-args since r10-7515-g2c0fa3ecf70d199a

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100623

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
There seems to be some IR difference on the gimple level which might be making
this latent.
In GCC 11.2.0 we have (bn_add_words) :
  _2 = n_3 & -4;
...
  if (_2 != 0)

While on the trunk we have:
  _14 = (unsigned int) n_3;
  if (_14 > 3)

This does look like a valid transformation knowing that n is subtracted by 4.