[Bug tree-optimization/100082] missed optimization for dead code elimination at -O3 (vs. -O2)

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100082

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
           Keywords|                            |missed-optimization
            Version|unknown                     |11.0
   Last reconfirmed|                            |2021-04-15

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.  At -O2 PRE manages to optimize the call to foo.  The difference
starts at cunrolli where -O3 unrolls but -O2 not, disabling cunrolli restores
optimization.