[Bug tree-optimization/123606] 5-8% slowdown of mcf on x86 caused by r16-6679-g3ebe697f32197e (was sped up by r16-5258-g1d8e2d51e5c5cb)

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123606

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2026-01-16
           Assignee|unassigned at gcc dot gnu.org      |pinskia at gcc dot 
gnu.org
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=123518
            Summary|5-8% slowdown of mcf on x86 |5-8% slowdown of mcf on x86
                   |since                       |caused by
                   |r16-6679-g3ebe697f32197e    |r16-6679-g3ebe697f32197e
                   |                            |(was sped up by
                   |                            |r16-5258-g1d8e2d51e5c5cb)
   Target Milestone|16.0                        |---
             Status|UNCONFIRMED                 |ASSIGNED
     Ever confirmed|0                           |1

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.
This was not a regression. The speed up was caused by r16-5258-g1d8e2d51e5c5cb
in the first place which what r16-6679-g3ebe697f32197e is fixing.
But I have not looked into how/why though.

Maybe the fix for PR 123518 will fix improve this. 

But this tells me there is some missed optimization in mcf that is not caught.