[Bug target/113257] -march=native or -mcpu=native are ineffective, but -march=native -mcpu=native works on arm64 M2 Ultra

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113257

--- Comment #13 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-13 branch has been updated by Tamar Christina
<tnfch...@gcc.gnu.org>:

https://gcc.gnu.org/g:eb45b829bb3fb658aa34a340264dee9755d34e69

commit r13-9351-geb45b829bb3fb658aa34a340264dee9755d34e69
Author: Tamar Christina <tamar.christ...@arm.com>
Date:   Thu Jan 16 19:25:26 2025 +0000

    AArch64: have -mcpu=native detect architecture extensions for unknown
non-homogenous systems [PR113257]

    in g:e91a17fe39c39e98cebe6e1cbc8064ee6846a3a7 we added the ability for
    -mcpu=native on unknown CPUs to still enable architecture extensions.

    This has worked great but was only added for homogenous systems.

    However the same thing works for big.LITTLE as in such system the cores
must
    have the same extensions otherwise it doesn't fundamentally work.

    i.e. task migration from one core to the other wouldn't work.

    This extends the same handling to non-homogenous systems.

    gcc/ChangeLog:

            PR target/113257
            * config/aarch64/driver-aarch64.cc (get_cpu_from_id, DEFAULT_CPU):
New.
            (host_detect_local_cpu): Use it.

    gcc/testsuite/ChangeLog:

            PR target/113257
            * gcc.target/aarch64/cpunative/info_34: New test.
            * gcc.target/aarch64/cpunative/native_cpu_34.c: New test.
            * gcc.target/aarch64/cpunative/info_35: New test.
            * gcc.target/aarch64/cpunative/native_cpu_35.c: New test.

    Co-authored-by: Richard Sandiford <richard.sandif...@arm.com>
    (cherry picked from commit 1ff85affe46623fe1a970de95887df22f4da9d16)