[Bug ipa/122856] [13/14/15 Regression] ICE: in decide_about_value, at ipa-cp.cc

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122856

--- Comment #8 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-13 branch has been updated by Martin Jambor
<jamborm@gcc.gnu.org>:

https://gcc.gnu.org/g:acce7073fb3397e6873bc54d223699c5db143721

commit r13-10226-gacce7073fb3397e6873bc54d223699c5db143721
Author: Martin Jambor <mjambor@suse.cz>
Date:   Fri Feb 20 14:34:27 2026 +0100

    ipa-cp: Also look at self-recursive ancestor jump functions (PR122856)

    PR 122856 shows that when looking at self recursive calls with
    self-feeding jump functions, we did consider pass-through functions
    but not ancestor functions with zero offsets.  This then leads to the
    fact that constants which were collected from IPA-CP lattices were not
    among those collected from available edges, triggering a verification
    assert.

    This patch fixes that by also detecting self-feeding ancestor jump
    functions.

    gcc/ChangeLog:

    2026-02-06  Martin Jambor  <mjambor@suse.cz>

            PR ipa/122856
            * ipa-cp.cc (self_recursive_pass_through_p): Test jump function
type first.
            (self_recursive_ancestor_p): New function.
            (find_scalar_values_for_callers_subset): Test also for
self-recursive
            ancestor jump functions.
            (push_agg_values_for_index_from_edge): Likewise.

    gcc/testsuite/ChangeLog:

    2026-02-06  Martin Jambor  <mjambor@suse.cz>

            PR ipa/122856
            * g++.dg/ipa/pr122856.C: New test.

    (cherry picked from commit e47f44074a5fe9b51cbe75269363a42e90d6a580)