[Bug target/121441] New: [16 Regression] 5% slowdown of 519.lbm_r on aarch64

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121441

            Bug ID: 121441
           Summary: [16 Regression] 5% slowdown of 519.lbm_r on aarch64
           Product: gcc
           Version: 16.0
            Status: UNCONFIRMED
          Keywords: missed-optimization, needs-bisection
          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=585.477.0

there was a 5% exec time slowdown of the 519.lbm_r SPEC 2017 benchmark between
commits

r16-2456-g556ed247adc985
r16-2619-g688f1947bd5453

when run with -Ofast (generic march) on an Ampere Altra (Neoverse N1) machine.


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)