[Bug tree-optimization/108523] [13 Regression] -O1 -fcode-hoisting causes long compilation time ?

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108523

--- Comment #13 from CVS 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:c29d85359add807200a1a851026b4e4a9d6b714c

commit r13-5348-gc29d85359add807200a1a851026b4e4a9d6b714c
Author: Richard Biener <rguenther@suse.de>
Date:   Wed Jan 25 13:31:46 2023 +0100

    tree-optimization/108523 - fix endless iteration in VN

    The following fixes not converging iteration in value-numbering of
    PHI nodes when we use an equivalence to prove the PHI node is
    degenerate.  We have to avoid the situation where we oscillate
    between the two equivalent values because the result is fed back
    via a backedge.

            PR tree-optimization/108523
            * tree-ssa-sccvn.cc (visit_phi): Avoid using the exclusive
            backedge value for the result when using predication to
            prove equivalence.