[Bug tree-optimization/127912] GCC fails to vectorize a negative step conditional store

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127912

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
             Target|                            |x86_64 aarch64
            Summary|[x86-64] GCC fails to       |GCC fails to vectorize a
                   |vectorize a reverse loop    |negative step conditional
                   |with a conditional store    |store
   Last reconfirmed|                            |2026-10-17
           Severity|normal                      |enhancement
             Status|UNCONFIRMED                 |NEW

--- Comment #1 from Drea Pinski <pinskia at gcc dot gnu.org> ---
Confirmed:
/app/example.cpp:5:27: note:   negative step with invariant source; no permute
needed.
/app/example.cpp:5:27: missed:   unsupported access type for masked store.
/app/example.cpp:7:20: missed:   not vectorized: relevant stmt not supported:
.MASK_STORE (_5, 32B, _26, 1);