[Bug target/126081] [16 Regression] or1k: ICE when compiling busybox nc_bloaty.c after 16.1.0

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126081

--- Comment #12 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-16 branch has been updated by Stafford Horne
<shorne@gcc.gnu.org>:

https://gcc.gnu.org/g:e748bc14649a16b25c3655dd393d9844480a5609

commit r16-9241-ge748bc14649a16b25c3655dd393d9844480a5609
Author: Stafford Horne <shorne@gmail.com>
Date:   Sat Jul 4 10:51:59 2026 +0100

    or1k: Stop allowing referring to SR_F in SImode and fix cmov

    We were seeing compiler errors such as:

        x.c:8:1: error: insn does not satisfy its constraints:
            8 | }
              | ^
        (insn 33 28 35 2 (set (reg:SI 34 ?sr_f)
                (reg:SI 16 r17 [52])) "x.c":6:7 discrim 1 28 {*movsi_internal}
             (nil))
        during RTL pass: postreload

    This was being caused by previous commit c0694f95f59 ("or1k: Fix ICE in
    libgcc caused by recent validate_subreg changes") and commit 710581c80b2
    ("or1k: Allow SImode for condition flag register") which allow
    referecing SR_F in SImode to avoid errors during if conversion.

    We can completely avoid this by reverting the changes to allow
    referencing SR_F in SImode and fixing the
    or1k_noce_conversion_profitable_p function to allow cmov expansion even
    when TARGET_CMOV is not enabled.  The *cmov split logic can take care of
    lowering the *cmov instructions if l.cmov is not supported during the
    later split passes.

    gcc/

            PR target/126081
            * config/or1k/or1k.cc (or1k_hard_regno_mode_ok): Stop allowing
            SImode for FLAG_REGS.
            (or1k_can_change_mode_class): Stop allowing SImode for
            FLAG_REGS.
            (or1k_noce_conversion_profitable_p): Always check
            or1k_is_cmov_insn.

    gcc/testsuite/

            PR target/126081
            * gcc.target/or1k/pr126081.c: New test.

    (cherry picked from commit 217a7679f4e50028f62f737c5906e3281c700ddc)