[Bug target/120226] New: 8% regression of exchange2 with -O2 between g:d0571638a6bad932 and g:9b13bea07706a7ca

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120226

            Bug ID: 120226
           Summary: 8% regression of exchange2 with -O2 between
                    g:d0571638a6bad932 and g:9b13bea07706a7ca
           Product: gcc
           Version: 16.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hubicka at gcc dot gnu.org
  Target Milestone: ---

This is visible on both Zen and Intel testers
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=298.407.0
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=800.407.0

I believe it is likely the costing of scatter which now disables vectorization
at generic tuning.

curiously, however there is also a regression at ARM
https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=581.407.0

so it may be something else...