[Bug target/119159] New: [15 Regression] 6% slowdown of 520.omnetpp_r on aarch64

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119159

            Bug ID: 119159
           Summary: [15 Regression] 6% slowdown of 520.omnetpp_r on
                    aarch64
           Product: gcc
           Version: 15.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pheeck at gcc dot gnu.org
            Blocks: 26163
  Target Milestone: ---
              Host: aarch64-gnu-linux
            Target: aarch64-gnu-linux

As seen here

https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.0=688.357.0

there was a 6% exec time slowdown of the 520.omnetpp_r SPEC 2017 benchmark
between commits

r15-7594-g565d4e755498ad
r15-7688-g6be1b9e94d9a2e

when run with -O2 -march=generic -flto PGO on an Ampere Altra Neoverse N1
machine.

I think this is a regression against GCC 14.  See the comparison
with GCC 14:

https://lnt.opensuse.org/db_default/v4/SPEC/graph?plot.6=1080.357.0&plot.7=688.357.0&;


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=26163
[Bug 26163] [meta-bug] missed optimization in SPEC (2k17, 2k and 2k6 and 95)