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From: "cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/114924] [11/12/13/14 Regression] Wrong update
 of MEM_EXPR by RTL loop unrolling since r11-2963-gd6a05b494b4b71
Date: Fri, 03 May 2024 12:48:26 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D114924

--- Comment #2 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-14 branch has been updated by Alex Coplan
<acoplan@gcc.gnu.org>:

https://gcc.gnu.org/g:242fbc0df6c23115c47d256e66fba6a770265c5d

commit r14-10160-g242fbc0df6c23115c47d256e66fba6a770265c5d
Author: Alex Coplan <alex.coplan@arm.com>
Date:   Fri May 3 09:23:59 2024 +0100

    cfgrtl: Fix MEM_EXPR update in duplicate_insn_chain [PR114924]

    The PR shows that when cfgrtl.cc:duplicate_insn_chain attempts to
    update the MR_DEPENDENCE_CLIQUE information for a MEM_EXPR we can end up
    accidentally dropping (e.g.) an ARRAY_REF from the MEM_EXPR and end up
    replacing it with the underlying MEM_REF.  This leads to an
    inconsistency in the MEM_EXPR information, and could lead to wrong code.

    While the walk down to the MEM_REF is necessary to update
    MR_DEPENDENCE_CLIQUE, we should use the outer tree expression for the
    MEM_EXPR.  This patch does that.

    gcc/ChangeLog:

            PR rtl-optimization/114924
            * cfgrtl.cc (duplicate_insn_chain): When updating MEM_EXPRs,
            don't strip (e.g.) ARRAY_REFs from the final MEM_EXPR.

    (cherry picked from commit fe40d525619eee9c2821126390df75068df4773a)=