[Bug tree-optimization/112312] -O3 produces worse code than -O2 for std::ranges::lower_bound in some cases, not marking a loop as finite

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112312

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2023-10-31
     Ever confirmed|0                           |1
            Summary|-O3 produces worse code     |-O3 produces worse code
                   |than -O2 for                |than -O2 for
                   |std::ranges::lower_bound in |std::ranges::lower_bound in
                   |some cases, not removing an |some cases, not marking a
                   |empty loop                  |loop as finite
             Status|UNCONFIRMED                 |NEW

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.

So further difference is the loop seems not to be marked as finite while with
-O2 (or the non-lamdba version) is.

Someone will need to figure out if and where we lose the idea of the finite
loopness.