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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 target/110591] [i386] (Maybe) Missed optimisation: _cmpccxadd sets flags
Date: Tue, 18 Jul 2023 03:31:48 +0000	[thread overview]
Message-ID: <bug-110591-4-twxrZBMiKk@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-110591-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110591

--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by hongtao Liu <liuhongt@gcc.gnu.org>:

https://gcc.gnu.org/g:06cc38c1c350b34cbd6dde23aefca32442c07a73

commit r14-2595-g06cc38c1c350b34cbd6dde23aefca32442c07a73
Author: liuhongt <hongtao.liu@intel.com>
Date:   Mon Jul 10 14:12:07 2023 +0800

    Add peephole to eliminate redundant comparison after cmpccxadd.

    Similar like we did for cmpxchg, but extended to all
    ix86_comparison_int_operator since cmpccxadd set EFLAGS exactly same
    as CMP.

    When operand order in compare insn is same as that in cmpccxadd,
    compare insn can be eliminated directly.

    When operand order is swapped in compare insn, only optimize cmpccxadd
    + cmpl + jcc/setcc to cmpccxadd + jcc/setcc when FLAGS_REG is dead
    after jcc/setcc.

    gcc/ChangeLog:

            PR target/110591
            * config/i386/sync.md (cmpccxadd_<mode>): Adjust the pattern
            to explicitly set FLAGS_REG like *cmp<mode>_1, also add extra
            3 define_peephole2 after the pattern.

    gcc/testsuite/ChangeLog:

            * gcc.target/i386/pr110591.c: New test.
            * gcc.target/i386/pr110591-2.c: New test.

  parent reply	other threads:[~2023-07-18  3:31 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-07 17:13 [Bug target/110591] New: " thiago at kde dot org
2023-07-10  2:21 ` [Bug target/110591] " crazylht at gmail dot com
2023-07-10  4:27 ` crazylht at gmail dot com
2023-07-10  6:22 ` crazylht at gmail dot com
2023-07-18  3:31 ` cvs-commit at gcc dot gnu.org [this message]
2023-07-18  3:32 ` crazylht at gmail dot com
2023-11-30 10:53 ` liuhongt at gcc dot gnu.org

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