[Bug tree-optimization/119103] Very suboptimal AVX2 code generation of simple shift loop

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119103

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |missed-optimization
           Severity|normal                      |enhancement
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2025-03-03

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
  # RANGE [irange] int [0, 65535] MASK 0xffff VALUE 0x0
  _5 = (intD.6) _4;
  # RANGE [irange] int [0, 15] MASK 0xf VALUE 0x0
  _6 = (intD.6) amount_11(D);
  # RANGE [irange] int [0, 2147450880] MASK 0x7fffffff VALUE 0x0
  _7 = _5 << _6;
  _8 = (short unsigned intD.18) _7;


That should be able to reduce down to just:
_8 = _4 << _6;

Since _6 has a range for [0,15] so we know it is defined.

I suspect once that happens the other part will be optimized.