[Bug tree-optimization/113144] [14 regression] ICE when building dpkg-1.21.15 in verify_dominators (error: dominator of 9 should be 48, not 12)

["cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113144

--- Comment #16 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Tamar Christina <tnfchris@gcc.gnu.org>:

https://gcc.gnu.org/g:9e7c77c7933b1bb0dd07214333e52a9a896fa349

commit r14-7101-g9e7c77c7933b1bb0dd07214333e52a9a896fa349
Author: Tamar Christina <tamar.christina@arm.com>
Date:   Wed Jan 10 12:51:54 2024 +0000

    middle-end: Fix dominators updates when peeling with multiple exits
[PR113144]

    When we peel at_exit we are moving the new loop at the exit of the previous
    loop.  This means that the blocks outside the loop dat the previous loop
used to
    dominate are no longer being dominated by it.

    The new dominators however are hard to predict since if the loop has
multiple
    exits and all the exits are an "early" one then we always execute the
scalar
    loop.  In this case the scalar loop can completely dominate the new loop.

    If we later have skip_vector then there's an additional skip edge added
that
    might change the dominators.

    The previous patch would force an update of all blocks reachable from the
new
    exits.  This one updates *only* blocks that we know the scalar exits
dominated.

    For the examples this reduces the blocks to update from 18 to 3.

    gcc/ChangeLog:

            PR tree-optimization/113144
            PR tree-optimization/113145
            * tree-vect-loop-manip.cc (slpeel_tree_duplicate_loop_to_edge_cfg):
            Update all BB that the original exits dominated.

    gcc/testsuite/ChangeLog:

            PR tree-optimization/113144
            PR tree-optimization/113145
            * gcc.dg/vect/vect-early-break_94-pr113144.c: New test.