[Bug tree-optimization/111519] [13/14 Regression] Wrong code at -O3 on x86_64-linux-gnu since r13-455-g1fe04c497d

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111519

--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:e75bf1985fdc9a5d3a307882a9251d8fd6e93def

commit r14-4552-ge75bf1985fdc9a5d3a307882a9251d8fd6e93def
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Wed Oct 11 08:58:29 2023 +0200

    tree-ssa-strlen: optimization skips clobbering store [PR111519]

    The following testcase is miscompiled, because count_nonzero_bytes
incorrectly
    uses get_strinfo information on a pointer from which an earlier instruction
    loads SSA_NAME stored at the current instruction.  get_strinfo shows a
state
    right before the current store though, so if there are some stores in
between
    the current store and the load, the string length information might have
    changed.

    The patch passes around gimple_vuse from the store and punts instead of
using
    strinfo on loads from MEM_REF which have different gimple_vuse from that.

    2023-10-11  Richard Biener  <rguenther@suse.de>
                Jakub Jelinek  <jakub@redhat.com>

            PR tree-optimization/111519
            * tree-ssa-strlen.cc (strlen_pass::count_nonzero_bytes): Add vuse
            argument and pass it through to recursive calls and
            count_nonzero_bytes_addr calls.  Don't shadow the stmt argument,
but
            change stmt for gimple_assign_single_p statements for which we
don't
            immediately punt.
            (strlen_pass::count_nonzero_bytes_addr): Add vuse argument and pass
            it through to recursive calls and count_nonzero_bytes calls.  Don't
            use get_strinfo if gimple_vuse (stmt) is different from vuse. 
Don't
            shadow the stmt argument.

            * gcc.dg/torture/pr111519.c: New testcase.