[Bug tree-optimization/118976] [12/13/14/15 regression] Correctness Issue: SVE vectorization results in data corruption when cpu has 128bit vectors but compiled with -mcpu=neoverse-v1 (which is only for 256bit vector cpus)

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118976

Tamar Christina <tnfchris at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
          Component|target                      |tree-optimization
   Last reconfirmed|                            |2025-02-24
                 CC|                            |tnfchris at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #11 from Tamar Christina <tnfchris at gcc dot gnu.org> ---
Confirmed.

As Kyrill mentioned, -mcpu=<core|native> always keeps SVE code VLA.

I think there are two bugs here. I think it's tree-cunroll that's transforming
the VLA code into the broken VLS code.

Could you try with  -fdisable-tree-cunroll?

PS. It's still on trunk if you do -fno-vect-cost-model