[Bug tree-optimization/112961] [13/14 Regression] middle-end Missed vectorization: failed to vectorize simple reduction max since GCC-13

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112961

--- Comment #5 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Richard Biener <rguenth@gcc.gnu.org>:

https://gcc.gnu.org/g:878cb5acf0c499702ffd315e273f55e8bd0970b8

commit r14-6457-g878cb5acf0c499702ffd315e273f55e8bd0970b8
Author: Richard Biener <rguenther@suse.de>
Date:   Tue Dec 12 14:01:47 2023 +0100

    tree-optimization/112961 - include latch in if-conversion CSE

    The following makes sure to also process the (empty) latch when
    performing CSE on the if-converted loop body.  That's important
    to get all uses of copies propagated out on the backedge as well.
    To avoid CSE on the PHI nodes itself which is prohibitive
    (see PR90402) this temporarily adds a fake entry edge to the loop.

            PR tree-optimization/112961
            * tree-if-conv.cc (tree_if_conversion): Instead of excluding
            the latch block from VN, add a fake entry edge.

            * g++.dg/vect/pr112961.cc: New testcase.