[Bug tree-optimization/125290] [16 Regression] ICE at -O3 during GIMPLE pass: ifcvt

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125290

--- Comment #8 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-16 branch has been updated by Andrea Pinski
<[email protected]>:

https://gcc.gnu.org/g:8a8b309e0ec8447ad08e3d1c99b3b37e18272f02

commit r16-9411-g8a8b309e0ec8447ad08e3d1c99b3b37e18272f02
Author: Andrew Pinski <[email protected]>
Date:   Wed May 13 21:24:43 2026 -0700

    tree-cfg: Revert part of r8-546 [PR125290]

    This reverts the group_case_labels_stmt part of r8-546-gca4d2851687875.
    This is placed in the wrong location to remove the case statements that go
    directly to __builtin_unreachable. In fact the removal of the case
statements
    make us lose optimizations in some cases (Wuninitialized-pr107919-1.C for
one).

    Also this fixes PR 125290 by no longer leaving around a switch which just
    has a default case.

    Bootstrapped and tested on x86_64-linux-gnu.

            PR tree-optimization/125290

    gcc/ChangeLog:

            * tree-cfg.cc (group_case_labels_stmt): Remove code that was
            added to remove `cases` that goto blocks of unreachable.
            * tree-ssa-forwprop.cc (optimize_unreachable): Remove the
            comment about switch cases being handled.

    gcc/testsuite/ChangeLog:

            * g++.dg/warn/Wuninitialized-pr107919-1.C: Remove xfail.
            * gcc.dg/analyzer/taint-assert.c: Update for the non-removal
            of block containing unreachable.
            * gcc.dg/torture/pr125290-1.c: New test.

    Signed-off-by: Andrew Pinski <[email protected]>
    (cherry picked from commit f108e23d2bff50d0ee8cf0d25a08be5432b702b6)